1.在页面加载完全中执行js代码:
在页面 "<script" 标签中添加属性:defer="defer" 即可!
例如:
<script language="javascript" type="text/javascript" src="
http://xx.com/abc.js " defer="true"></script>
这段script要放在<head></head>之间.而且在脚本中不能有document.write()方法.因为设置了defer="true"的脚本是页面加载之后才加载并渲染的.如果这时候使用document.write()方法,会把之前的页面内容都清掉.
2.获取地址栏字符串
location.href
3.防止表单重复提交
例子:
<form name="form1" method="post" action="" onSubmit='submitonce(this)'>
........
function submitonce(theform) {
if (document.all||document.getElementById) {
for (i=0;i<theform.length;i++) {
var tempobj=theform.elements[i];
if(tempobj.type.toLowerCase()=="submit" || tempobj.type.toLowerCase()=="reset") tempobj.disabled=true;
}
}
}
4.关于浮动代码和 documentElement / body
常常有人提问,为什么 漂浮广告 / 对联代码 在 xHTML 1.1 DTD 文件头 / FF 下不能使用
这是因为,按照标准来说,我们看到的窗体的滚动条不应该是 body 的,而是 HTML 的(也就是 document.documentElement 对象)
所以,解决办法是,把以前不标准的代码中, document.body.scrollTop 或者类似的代码变换为 document.documentElement.scrollTop
5.关于图片缩小放大
<script language="JavaScript">
<!--
//改变图片大小
function resizepic(thispic)
{
if(thispic.width>700) thispic.width=700;
}
//无级缩放图片大小
function bbimg(o)
{
var zoom=parseInt(o.style.zoom, 10)||100;
zoom+=event.wheelDelta/12;
if (zoom>0) o.style.zoom=zoom+'%';
return false;
}
-->
</script>
<P align=center><IMG onmousewheel="return bbimg(this)" height=341
src="http://bbs.blueidea.com/images/blue/logo.gif"
onload=javascript:resizepic(this) border=0></P>
6.用JS来处理图片变形的问题,等比例缩放图片,还能防止图片在加载过程中因为图片太大而引起的变形
<script language="JavaScript" type="text/javascript">
<!--
function DrawImage(ImgD,FitWidth,FitHeight){
var image=new Image();
image.src=ImgD.src;
if(image.width>0 && image.height>0){
if(image.width/image.height>= FitWidth/FitHeight){
if(image.width>FitWidth){
ImgD.width=FitWidth;
ImgD.height=(image.height*FitWidth)/image.width;
}else{
ImgD.width=image.width;
ImgD.height=image.height;
}
} else{
if(image.height>FitHeight){
ImgD.height=FitHeight;
ImgD.width=(image.width*FitHeight)/image.height;
}else{
ImgD.width=image.width;
ImgD.height=image.height;
}
}
}
}
//-->
</script>
<img src="
http://chenefei.com/upload/Gtalk.jpg " alt="自动缩放后的效果" width="200" height="200" onload="javascript:DrawImage(this,"200","200");" />
=========================================================附网络收集js技巧==============================================
js技巧集锦
javascript小技巧-js小技巧收集(转)
每一项都是js中的小技巧,但十分的实用!
1.document.write(""); 输出语句
2.JS中的注释为//
3.传统的HTML文档顺序是:document->html->(head,body)
4.一个浏览器窗口中的DOM顺序是:window->(navigator,screen,history,location,document)
5.得到表单中元素的名称和值:document.getElementById("表单中元素的ID号").name(或value)
6.一个小写转大写的JS: document.getElementById("output").value = document.getElementById("i
nput").value.toUpperCase();
7.JS中的值类型:String,Number,Boolean,Null,Object,Function
8.JS中的字符型转换成数值型:parseInt(),parseFloat()
9.JS中的数字转换成字符型:(""+变量)
10.JS中的取字符串长度是:(length)
11.JS中的字符与字符相连接使用+号.
12.JS中的比较操作符有:==等于,!=不等于,>,>=,<.<=
13.JS中声明变量使用:var来进行声明
14.JS中的判断语句结构:if(condition){}else{}
15.JS中的循环结构:for([initial expression];[condition];[upadte expression]) {inside loop}
16.循环中止的命令是:break
17.JS中的函数定义:function functionName([parameter],...)
18.当文件中出现多个form表单时.可以用document.forms[0],document.forms[1]来代替.
19.窗口:打开窗口window.open(), 关闭一个窗口:window.close(), 窗口本身:self
20.状态栏的设置:window.status="字符";
21.弹出提示信息:window.alert("字符");
22.弹出确认框:window.confirm();
23.弹出输入提示框:window.prompt();
24.指定当前显示链接的位置:window.location.href="URL"
25.取出窗体中的所有表单的数量:document.forms.length
26.关闭文档的输出流:document.close();
27.字符串追加连接符:+=
28.创建一个文档元素:document.createElement(),document.createTextNode()
29.得到元素的方法:document.getElementById()
30.设置表单中所有文本型的成员的值为空:
var form = window.document.forms[0]
for (var i = 0; i if (form.elements.type == "text"){
form.elements.value = "";
}
}
31.复选按钮在JS中判断是否选中:document.forms[0].checkThis.checked (checked属性代表为是否选中
返回TRUE或FALSE)
32.单选按钮组(单选按钮的名称必须相同):取单选按钮组的长度document.forms[0].groupName.length
33.单选按钮组判断是否被选中也是用checked.
34.下拉列表框的值:document.forms[0].selectName.options[n].value (n有时用下拉列表框名称加上.sel
ectedIndex来确定被选中的值)
35.字符串的定义:var myString = new String("This is lightsword");
36.字符串转成大写:string.toUpperCase(); 字符串转成小写:string.toLowerCase();
37.返回字符串2在字符串1中出现的位置:String1.indexOf("String2")!=-1则说明没找到.
38.取字符串中指定位置的一个字符:StringA.charAt(9);
39.取出字符串中指定起点和终点的子字符串:stringA.substring(2,6);
40.数学函数:Math.PI(返回圆周率),Math.SQRT2(返回开方),Math.max(value1,value2)返回两个数中的最
在值,Math.pow(value1,10)返回value1的十次方,Math.round(value1)四舍五入函数,Math.floor(Math.ra
ndom()*(n+1))返回随机数
41.定义日期型变量:var today = new Date();
42.日期函数列表:dateObj.getTime()得到时间,dateObj.getYear()得到年份,dateObj.getFullYear()得到
四位的年份,dateObj.getMonth()得到月份,dateObj.getDate()得到日,dateObj.getDay()得到日期几,dat
eObj.getHours()得到小时,dateObj.getMinutes()得到分,dateObj.getSeconds()得到秒,dateObj.setTi
me(value)设置时间,dateObj.setYear(val)设置年,dateObj.setMonth(val)设置月,dateObj.setDate(va
l)设置日,dateObj.setDay(val)设置星期几,dateObj.setHours设置小时,dateObj.setMinutes(val)设置分,
dateObj.setSeconds(val)设置秒 [注意:此日期时间从0开始计]
43.FRAME的表示方式: [window.]frames[n].ObjFuncVarName,frames["frameName"].ObjFuncVarN
ame,frameName.ObjFuncVarName
44.parent代表父亲对象,top代表最顶端对象
45.打开子窗口的父窗口为:opener
46.表示当前所属的位置:this
47.当在超链接中调用JS函数时用:(javascript :)来开头后面加函数名
48.在老的浏览器中不执行此JS:
49.引用一个文件式的JS:
50.指定在不支持脚本的浏览器显示的HTML:
51.当超链和onCLICK事件都有时,则老版本的浏览器转向a.html,否则转向b.html.例:dfsadf
52.JS的内建对象有:Array,Boolean,Date,Error,EvalError,Function,Math,Number,Object,RangeError,
ReferenceError,RegExp,String,SyntaxError,TypeError,URIError
53.JS中的换行:\n
54.窗口全屏大小:
55.JS中的all代表其下层的全部元素
56.JS中的焦点顺序:document.getElementByid("表单元素").tabIndex = 1
57.innerHTML的值是表单元素的值:如
"how are you"
,则innerHTML的值就是:how are you
58.innerTEXT的值和上面的一样,只不过不会把这种标记显示出来.
59.contentEditable可设置元素是否可被修改,isContentEditable返回是否可修改的状态.
60.isDisabled判断是否为禁止状态.disabled设置禁止状态
61.length取得长度,返回整型数值
62.addBehavior()是一种JS调用的外部函数文件其扩展名为.htc
63.window.focus()使当前的窗口在所有窗口之前.
64.blur()指失去焦点.与FOCUS()相反.
65.select()指元素为选中状态.
66.防止用户对文本框中输入文本:onfocus="this.blur()"
67.取出该元素在页面中出现的数量:document.all.tags("div(或其它HTML标记符)").length
68.JS中分为两种窗体输出:模态和非模态.window.showModaldialog(),window.showModeless()
69.状态栏文字的设置:window.status='文字',默认的状态栏文字设置:window.defaultStatus = '文字.';
70.添加到收藏夹:external.AddFavorite("http://www.dannyg.com "t;,"jaskdlf");
71.JS中遇到脚本错误时不做任何操作:window.onerror = doNothing; 指定错误句柄的语法为:window.on
error = handleError;
72.JS中指定当前打开窗口的父窗口:window.opener,支持opener.opener...的多重继续.
73.JS中的self指的是当前的窗口
74.JS中状态栏显示内容:window.status="内容"
75.JS中的top指的是框架集中最顶层的框架
76.JS中关闭当前的窗口:window.close();
77.JS中提出是否确认的框:if(confirm("Are you sure?"))else{alert("Not Ok");}
78.JS中的窗口重定向:window.navigate("http://www.sina.com.cn "t;);
79.JS中的打印:window.print()
80.JS中的提示输入框:window.prompt("message","defaultReply");
81.JS中的窗口滚动条:window.scroll(x,y)
82.JS中的窗口滚动到位置:window.scrollby
83.JS中设置时间间隔:setInterval("expr",msecDelay)或setInterval(funcRef,msecDelay)或setTimeou
t
84.JS中的模态显示在IE4+行,在NN中不行:showModalDialog("URL"[,arguments][,features]);
85.JS中的退出之前使用的句柄:function verifyClose(){event.returnValue="we really like you and ho
pe you will stay longer.";}} window.onbeforeunload=verifyClose;
86.当窗体第一次调用时使用的文件句柄:onload()
87.当窗体关闭时调用的文件句柄:onunload()
88.window.location的属性: protocol(http:),hostname(example.com),port(80),host(e
xample.com:80),pathname("/a/a.html"),hash("#giantGizmo",指跳转到相应的锚记),href(全部的信
息)
89.window.location.reload()刷新当前页面.
90.window.history.back()返回上一页,window.history.forward()返回下一页,window.history.go(返回
第几页,也可以使用访问过的URL)
91.document.write()不换行的输出,document.writeln()换行输出
92.document.body.noWrap=true;防止链接文字折行.
93.变量名.charAt(第几位),取该变量的第几位的字符.
94."abc".charCodeAt(第几个),返回第几个字符的ASCii码值.
95.字符串连接:string.concat(string2),或用+=进行连接
96.变量.indexOf("字符",起始位置),返回第一个出现的位置(从0开始计算)
97.string.lastIndexOf(searchString[,startIndex])最后一次出现的位置.
98.string.match(regExpression),判断字符是否匹配.
99.string.replace(regExpression,replaceString)替换现有字符串.
100.string.split(分隔符)返回一个数组存储值.
101.string.substr(start[,length])取从第几位到指定长度的字符串.
102.string.toLowerCase()使字符串全部变为小写.
103.string.toUpperCase()使全部字符变为大写.
104.parseInt(string[,radix(代表进制)])强制转换成整型.
105.parseFloat(string[,radix])强制转换成浮点型.
106.isNaN(变量):测试是否为数值型.
107.定义常量的关键字:const,定义变量的关键字:var
--------------------------------------------------------------------------------------------------------------------------------
javascript38种小技巧,推荐新手查看。
事件源对象
event.srcElement.tagName
event.srcElement.type
捕获释放
event.srcElement.setCapture();
event.srcElement.releaseCapture();
事件按键
event.keyCode
event.shiftKey
event.altKey
event.ctrlKey
事件返回值
event.returnValue
鼠标位置
event.x
event.y
窗体活动元素
document.activeElement
绑定事件
document.captureEvents(Event.KEYDOWN);
访问窗体元素
document.all("txt").focus();
document.all("txt").select();
窗体命令
document.execCommand
窗体COOKIE
document.cookie
菜单事件
document.oncontextmenu
创建元素
document.createElement("SPAN");
根据鼠标获得元素:
document.elementFromPoint(event.x,event.y).tagName=="TD
document.elementFromPoint(event.x,event.y).appendChild(ms)
窗体图片
document.images[索引]
窗体事件绑定
document.onmousedown=scrollwindow;
元素
document.窗体.elements[索引]
对象绑定事件
document.all.xxx.detachEvent('onclick',a);
插件数目
navigator.plugins
取变量类型
typeof($js_libpath) == "undefined"
下拉框
下拉框.options[索引]
下拉框.options.length
查找对象
document.getElementsByName("r1");
document.getElementById(id);
定时
timer=setInterval('scrollwindow()',delay);
clearInterval(timer);
UNCODE编码
escape() ,unescape
父对象
obj.parentElement(dhtml)
obj.parentNode(dom)
交换表的行
TableID.moveRow(2,1) document.all.csss.href = "a.css";
替换CSS
并排显示
display:inline
隐藏焦点
hidefocus=true
根据宽度换行
style="word-break:break-all"
自动刷新
<meta HTTP-EQUIV="refresh" CONTENT="8;URL=http://c98.yeah.net">
简单邮件
<a href="mailto:aaa@bbb.com?subject=ccc&body=xxxyyy">
快速转到位置
obj.scrollIntoView(true)
锚
<a name="first">
<a href="#first">anchors</a>
网页传递参数
location.search();
可编辑
obj.contenteditable=true
执行菜单命令
obj.execCommand
双字节字符
/[^\x00-\xff]/
汉字
/[\u4e00-\u9fa5]/
让英文字符串超出表格宽度自动换行
word-wrap: break-word; word-break: break-all;
透明背景
<IFRAME src="1.htm" width=300 height=180 allowtransparency></iframe>
获得style内容
obj.style.cssText
HTML标签
document.documentElement.innerHTML
第一个style标签
document.styleSheets[0]
style标签里的第一个样式
document.styleSheets[0].rules[0]
防止点击空链接时,页面往往重置到页首端。
<a href="javascript:function()">word</a>
上一网页源
asp:
request.servervariables("HTTP_REFERER")
javascript:
document.referrer
释放内存
CollectGarbage();
禁止右键
document.oncontextmenu = function() { return false;}
禁止保存
<noscript><iframe src="*.htm"></iframe></noscript>
禁止选取<body oncontextmenu="return false" ondragstart="return false" onselectstart ="return false" onselect="document.selection.empty()" oncopy="document.selection.empty()" onbeforecopy="return false"onmouseup="document.selection.empty()>
禁止粘贴
<input type=text onpaste="return false">
地址栏图标
<link rel="Shortcut Icon" href="favicon.ico">
favicon.ico 名字最好不变16*16的16色,放虚拟目录根目录下
收藏栏图标
<link rel="Bookmark" href="favicon.ico">
查看源码
<input type=button value=查看网页源代码 onclick="window.location = 'view-source:'+ 'http://www.csdn.net/ '">
关闭输入法
<input style="ime-mode:disabled">
自动全选
<input type=text name=text1 value="123" onfocus="this.select()">
ENTER键可以让光标移到下一个输入框
<input onkeydown="if(event.keyCode==13)event.keyCode=9">
文本框的默认值
<input type=text value="123" onfocus="alert(this.defaultValue)">
title换行
obj.title = "123 sdfs "
获得时间所代表的微秒
var n1 = new Date("2004-10-10".replace(/-/g, "\/")).getTime()
窗口是否关闭
win.closed
checkbox扁平
<input type=checkbox style="position: absolute; clip:rect(5px 15px 15px 5px)"><br>
获取选中内容
document.selection.createRange().duplicate().text
自动完成功能
<input type=text autocomplete=on>打开该功能
<input type=text autocomplete=off>关闭该功能
窗口最大化
<body onload="window.resizeTo(window.screen.width - 4,window.screen.height-50);window.moveTo(-4,-4)">
无关闭按钮IE
window.open("aa.htm", "meizz", "fullscreen=7");
统一编码/解码
alert(decodeURIComponent(encodeURIComponent("http:// 你好.com?as= hehe")))
encodeURIComponent对":"、"/"、";" 和 "?"也编码
表格行指示
<tr onmouseover="this.bgColor='#f0f0f0'" onmouseout="this.bgColor='#ffffff'">
------------------------------------------------------------------------------------------------------------------------------------------------
核心(Core) Javascript 学习手记
核心(Core) Javascript 学习手记
linenum
CreateD BY STABX, AT 2006-9-5.
Javascript Notes By shawl.qiu
---/-------------------------------------------------------------
-3.1 函数比其他代码优先执行
-3. 优先级
-2.4 同时初始化多个变量并赋相同值
-2.3 在函数中使用 var 定义一个变量, 该变量将影响整个函数, 不分先后.
-2.2 全局变量与局部变量
-2.1.2 普通定义变量 2
-2.1.1 普通定义变量 1
-2.1 普通定义变量
-2. var 定义变量
-1.5 in 操作符
-1.4.2 true 等价 1, false 等价 0.
-1.4 == 与 ===
-1.4.1 NaN
-1.3 0/0=?
-1.2 类型转换
-1.1 -- 与 ++
-1.1.1
-1. 运算符
0. 语法
0.1 Switch
1. 按钮
1.1 前进后退按钮
1.2 确认按钮
1.3 最原始也最实用的 UBB 代码输入方法——SCRIPT & FORM
1.4 Prompt
1.5.1 鼠标经过时选中,并隐藏原框的文字, 移开再显示文字 ——文本框
1.5 鼠标经过时选中 ——复选框 Focus()
1.6 鼠标经过自动提交表单
2. 接收键盘事件
2.1 按任何键关闭窗口
2.2 实时显示更改的图片链接
3. 数组/Array
3.1 Javascript 结合 Asp 使用数组
4. 控制图片大小
5. 双击拷贝文本
6. IE 全屏显示
7. 文本框回车链接
8. 顯示頁面所有元素
9. 正则表达式
10. 接收鼠标事件
10.1 单击鼠标右击关闭窗口 (我用左手)
10.2 鼠标移过选择表单项
11. 字符串
11.1 检测字符串中是否出现某字符
12. 随机数
12.1.1 生成 GUID 2
12.1 生成 GUID
13. 时间操作
13.1 以毫秒为单位的倒计时跳转, 来源 CSDN
14. switch
14.1 简单 switch
15 if 判断
15.1.2 简单 if 判断 3
15.1.1 简单 if 判断 2
15.1 简单 if 判断
15.2 if 判断的 三个 写法
15.3 判断执行文件使用网络还是使用本地协议
15.4 if...else 写法
16. 简单 while
16. while
17. do while
17.1.2 简单 do while
17.1 简单 do while
18. for
18.1 简单 for
18.2 简单 for 1
18.3 循环列出从 a - z 的字母
18.3 n阶乘
18.4 Fibonacci Numbers
19. for in
19.1.1 简单 for in 1
19.1 简单 for in
19.2.1 for in 赋值 [数组] 1
19.2 for in 赋值 [数组]
20. try, catch, finally
20.1.1 简单 try, catch 1
20.1 简单 try, catch
21. with
21.1 简单with (另一写法)
21.1 简单 with
22. break, continue
22.1 continue
22.2.1 break 标签
22.2 break
23. call, apply
23.1.1 找出数组中最大的数
23.1 apply
24. object
24.1.1 创建简单对象 一
24.1.2 创建简单对象 二
24.1 创建简单对象
24.2.1 创建嵌套对象 1
24.2 创建嵌套对象
24.3 删除对象中的属性
24.4.1 遍历对象中的属性名 1
24.4 遍历对象中的属性名
24.5 obj.propertyIsEnumerable('ele')
24.6 obj.hasOwnProperty('ele')
25. toString
25.1 使用 toString 列出数组中的元素
26. Array()
26.0.1 简单创建数组, 并赋值 2
26.0 简单创建数组, 并赋值
26.0.3 创建数组中的数组
26.0.4 创建数组中的对象
26.0.2 简单创建数组
26.1 [array].push(), [array].pop()
26.2 数组排序
26.3 创建数组指定维数, 从 1 开始.
27. RegExp
27.1 普通操作 1
27.2 test 语句
27.3 exec 语句
28. new 语法
29. isNaN
30. Date()
30.1 输出年月日, 时分秒 的日期格式
31. function 函数
31.1.1.1 三种定义函数的方法 1.1
31.10 在数组中存储函数, 并引用
31.1.1 三种定义函数的方法 1
31.1.2 三种定义函数的方法 2
31.1 三种定义函数的方法
31.2 在标签中写函数
31.3 创建嵌套函数
31.4.1 创建递归函数 1
31.4 创建递归函数
31.5 创建 函数对象
31.6 在函数内部定义的函数只能在该函数内部调用
31.7 定义函数变量, 并赋值
31.8 变量引用函数
31.9 在对象中存储函数, 并引用
31.11 function.call()
31.12 在函数内定义的变量可以被下级内嵌函数调用
32. typeof 查看数据类型
32.1
33. obj.valueOf() 返回原始值
34. Math 对象
34.1.1 生成 1 至 4 的随机数
34.1 Math.random();
34.2 求 x 的 n 次方
35. delete
36. confirm() 确认框
36.1 带条件确认框
37. window.open
37. window
37.1 打开没有焦点的窗口
38. return 返回值
38.1 return true
38.2 return undefined
39. throw
39.1 简单产生错误
40. arguments
40.1 判断 arguments.length
40.2 列出所有 argument 的值
40.3 arguments.callee / 调用函数本身
41. .to******
41.1 toString
42. parseInt() / parseFolat()
--------------------------------
42. parseInt() / parseFolat()
<script type="text/javascript">
//<![CDATA[
var str='1.1322 this test ';
document.write(('str like this: ').bold()+str.fontcolor('red')+'<br/>');
document.write(('parseInt(str): ').bold()+parseInt(str)+'<br/>');
document.write(('parseFloat(str): ').bold()+parseFloat(str)+'<br/>');
document.write(('parseInt(1111,2): ').bold()+parseInt(1111,2)+'<br/>');
document.write(('parseInt(1111,8): ').bold()+parseInt(1111,8)+'<br/>');
document.write(('parseInt(1111): ').bold()+parseInt(1111)+'<br/>');
document.write(('parseInt(1111,16): ').bold()+parseInt(1111,16)+'<br/>');
//]]>
</script>
41. .to******
<script type="text/javascript">
//<![CDATA[
var num=12345.6789
document.write(('parseInt(num): ').bold()+parseInt(num)+'<br/>');
document.write(('num.toFixed(0): ').bold()+num.toFixed(0)+'<br/>');
document.write(('num.toFixed(2): ').bold()+num.toFixed(2)+'<br/>');
document.write(('num.toExponential(2): ').bold()+num.toExponential(2)+'<br/>');
document.write(('num.toExponential(1): ').bold()+num.toExponential(1)+'<br/>');
document.write(('num.toPrecision(1): ').bold()+num.toPrecision(1)+'<br/>');
document.write(('num.toPrecision(2): ').bold()+num.toPrecision(2)+'<br/>');
//]]>
</script>
41.1 toString
<script type="text/javascript">
//<![CDATA[
var num=123456789
document.write(('num.toString(): ').bold()+num.toString()+'<br/>');
document.write(('num.toString(2): ').bold()+num.toString(2)+'<br/>');
document.write(("'0'+num.toString(8): ").bold()+'0'+num.toString(8)+'<br/>');
document.write(("'0x'+num.toString(16): ").bold()+'0x'+num.toString(16)+'<br/>');
//]]>
</script>
40. arguments
40.1 判断 arguments.length
<script type="text/javascript">
//<![CDATA[
function t(a, b, c, d){
if(arguments.length!=4)document.write(('error! argument must be 4 element.').fontcolor('red')+' current arguments length: '+arguments.length+'<br/>');
else document.write(('this right: '+arguments.length).bold()+' arguments<br/>');
}
t();
t('a', 'b', 'c', 'd');
t('a', 'b', 'c', 'd', 'e');
//]]>
</script>
40.2 列出所有 argument 的值
<script type="text/javascript">
//<![CDATA[
function t(){
for(var i=0; i<arguments.length; i++){
document.write(('arguments['+i+']').bold()+' = '+arguments[i].fontcolor('red')+'<br/>');
}
}
var temp='test';
t('aaa', 'bbb', 'ccc', 'ddd', 'eee', temp);
//]]>
</script>
40.3 arguments.callee / 调用函数本身
<script type="text/javascript">
//<![CDATA[
var t=function(x){
document.write(x+'<br/>');
if(x>1){
arguments.callee(x-1);
}
}
t(10);
//]]>
</script>
39. throw
39.1 简单产生错误
<script type="text/javascript">
//<![CDATA[
t(10);
t();
function t(x){
if(typeof x==='undefined')throw new Error('x must be own a value');
document.write(x);
}
//]]>
</script>
38. return 返回值
38.1 return true
<script type="text/javascript">
//<![CDATA[
function t(ipt){
window.status=ipt;
return true;
}
t('test this');
//]]>
</script>
38.2 return undefined
<script type="text/javascript">
//<![CDATA[
function t(t){
if(t==null)return;
}
document.write(t()); // undefined
//]]>
</script>
37. window
37. window.open
37.1 打开没有焦点的窗口
<script type="text/javascript">
//<![CDATA[
var w=window.open('/')
w.blur();
window.focus();
//]]>
</script>
36. confirm() 确认框
36.1 带条件确认框
<script type="text/javascript">
//<![CDATA[
var x=confirm('what doing with you')
if(x){alert('ok')}else alert('good choice');
//]]>
</script>
35. delete
<script type="text/javascript">
//<![CDATA[
var t={i:'ok', j:'ok too'}
document.write(delete t.i); // true
document.write('<br/>');
document.write(delete t); // false 不能删除 使用 var 定义的变量或对象
document.write('<br/>');
document.write(delete n); // true 删除不存在的元素.
document.write('<br/>');
document.write(delete j); // true
document.write('<br/>');
//]]>
</script>
34. Math 对象
34.1 Math.random();
34.1.1 生成 1 至 4 的随机数
<script type="text/javascript">
//<![CDATA[
document.write(parseInt(Math.random()*4+1)+'<br/>');
//]]>
</script>
34.2 求 x 的 n 次方
<script type="text/javascript">
//<![CDATA[
document.write(Math.pow(2,10));
//]]>
</script>
33. obj.valueOf() 返回原始值
<script type="text/javascript">
//<![CDATA[
var a=1, b='test', c=false, d=new Object();
document.write(a.valueOf()+'<br/>'); // 1
document.write(b.valueOf()+'<br/>'); // test
document.write(c.valueOf()+'<br/>'); // false
document.write(d.valueOf()+'<br/>'); // [object Object]
//]]>
</script>
32. typeof 查看数据类型
<script type="text/javascript">
//<![CDATA[
var a=['a', 'b', 'c']
document.write(typeof a); // object
document.write(a.valueOf()); // a, b, c
document.write(typeof null); // object
//]]>
</script>
32.1
<script type="text/javascript">
//<![CDATA[
var a=['a', 'b', 'c']
document.write(typeof a); // object
document.write(a.valueOf()); // a, b, c
//]]>
</script>
31. function 函数
31.1 三种定义函数的方法
<script type="text/javascript">
//<![CDATA[
function f(){ alert('function f');};
var f1=function(){ alert('function f1');};
var f2=new Function('', "alert('function f2')");
f(); f1(); f2();
//]]>
</script>
31.1.1 三种定义函数的方法 1
<script type="text/javascript">
//<![CDATA[
var t=new Function('a', 'b', 'return a+b;')
document.write(t('ok ', 'test this'));
//]]>
</script>
31.1.1.1 三种定义函数的方法 1.1
<script type="text/javascript">
//<![CDATA[
var t=new Function("return 'test this'")
document.write(t());
//]]>
</script>
31.1.2 三种定义函数的方法 2
<script type="text/javascript">
//<![CDATA[
var t=function(str){return 'this test'+str};
document.write(t(', right.'));
//]]>
</script>
31.2 在标签中写函数
<div onclick="javascript:var go=function(){alert(111)};go();">div 可用</div>
<div onclick="go()">div1 不可用</div>
<div onclick="javascript:( function(){alert(111);} )()">div2 可用</div>
<div onclick="javascript:function go(){alert(111);}go();">div3 可用</div>
31.3 创建嵌套函数
<script type="text/javascript">
//<![CDATA[
function level1(){
var lNm='level 1'
document.write(lNm+'<br/>');
function level2(){
var lNm='level 2'
document.write(lNm+'<br/>');
}
level2();
}
level1();
//]]>
</script>
31.4 创建递归函数
<%
var i=0;
function t(){
i++;
if(i<100){
Response.Write(i+'<br/>');
return t();
}
Response.Write(i+'<br/>');
}
t();
%>
31.4.1 创建递归函数 1
<script type="text/javascript">
//<![CDATA[
function fctr(n){
if(n<=1)return 1;
return n*fctr(n-1);
}
document.write(fctr(4));
//]]>
</script>
31.5 创建 函数对象
<script type="text/javascript">
//<![CDATA[
function fT(){
this.title='o test';
this.subtitle=fTt();
function fTt(){
return 'o subtitle';
}
}
var t=new fT();
document.write(t.title+'<br/>');
document.write(t.subtitle+'<br/>');
t=null;
//]]>
</script>
31.6 在函数内部定义的函数只能在该函数内部调用
<script type="text/javascript">
//<![CDATA[
function lev1(){
document.write('lev 1<br/>');
function lev2(){
document.write('lev 2<br/>');
}
lev2();
}
lev1();
lev2(); // 出错, 在函数内部定义的函数只能在该函数内部调用
//]]>
</script>
31.7 定义函数变量, 并赋值
<script type="text/javascript">
//<![CDATA[
var t=(function(str){return str+str+'<br/>';})('test this ')
document.write(t);
//]]>
</script>
31.8 变量引用函数
<script type="text/javascript">
//<![CDATA[
function t(x){
x+='';
return x+x;
}
document.write(t('how fun ')+'<br>'); // how fun how fun
var u=t // u 引用 函数 t
document.write(u('how fun too ')+'<br>'); // how fun too how fun too
//]]>
</script>
31.9 在对象中存储函数, 并引用
<script type="text/javascript">
//<![CDATA[
var o=new Object();
o.t=function(x){x+=''; return x+x;}
var t=o.t('test this ');
document.write(t);
//]]>
</script>
31.10 在数组中存储函数, 并引用
<script type="text/javascript">
//<![CDATA[
var a=new Array(3);
a[0]=function(x){x+='';return x+x};
a[1]='test this ';
a[2]=a[0](a[1]);
document.write(a[2]);
//]]>
</script>
31.11 function.call()
<script type="text/javascript">
//<![CDATA[
var o=new Object();
function f(a, b){
return a+b
}
document.write(f.call(o, 1, 2));
//]]>
</script>
31.12 在函数内定义的变量可以被下级内嵌函数调用
<script type="text/javascript">
//<![CDATA[
function t(){
var x=" this's test ";
function u(){
document.write(x.bold());
}
u();
}
t();
//]]>
</script>
30. Date()
30.1 输出年月日, 时分秒 的日期格式
<script type="text/javascript">
//<![CDATA[
var $dt=new Date();
document.write('yyyy-nn-dd: '+$dt.toLocaleDateString()+'<br/>');
document.write('hh-mm-ss: '+$dt.toLocaleTimeString());
//]]>
</script>
29. isNaN
<script type="text/javascript">
//<![CDATA[
var $str='this is string';
var $num=12.3;
//alert(isNaN($str));
alert(isNaN($num));
//]]>
</script>
28. new 语法
new Boolean(false)
new Number(0)
new String("")
new Array()
new Object()
new Date();
new Error();
27. RegExp
27.1 普通操作 1
<script type="text/javascript">
//<![CDATA[
var $str='this is a test'
with(document){
write('test str is: '+$str+'<br/>');
write('$str.search(/is a/i): '+$str.search(/is a/i)+'<p/>');
write('$str.replace(/ {1,1}/ig,"--"): '+$str.replace(/ {1,1}/ig,"--")+'<p/>');
write('$str.match(/t[\S]{1,3}/ig): '+$str.match(/t[\S]{1,3}/ig)+'<p/>');
var $temp=$str.match(/(t[\S]{1,3})/ig)
for ($i=0; $i<$temp.length; $i++){
write($temp[$i]+'<br/>');
}
}
//]]>
</script>
27.2 test 语句
<script type="text/javascript">
//<![CDATA[
var $pattern=/this/i;
alert($pattern.test('this is a test'));
//]]>
</script>
27.3 exec 语句
<script type="text/javascript">
//<![CDATA[
var $pattern=/this/ig;
var $str='this is a test, this is repeat';
var $result;
while(($result=$pattern.exec($str))!=null){
alert($result[0]+'>>> index of str: '+$result.index+' $pattern lastIndex: '+$pattern.lastIndex);
}
//]]>
</script>
26. Array()
26.0 简单创建数组, 并赋值
<script type="text/javascript">
//<![CDATA[
var ar=new Array();
for(var i=0; i<10; i++){
ar[i]='array '+i
document.write(ar[i]+'<br/>');
}
//]]>
</script>
26.0.1 简单创建数组, 并赋值 2
<script type="text/javascript">
//<![CDATA[
var ar=['v1', 'v2', 'v3', 'v4', 'v5']
for(var i=0; i<ar.length; i++){
document.write(ar[i]+'<br/>');
}
//]]>
</script>
26.0.2 简单创建数组
<script type="text/javascript">
//<![CDATA[
var ar=new Array(10);
document.write(ar.length);
//]]>
</script>
26.0.3 创建数组中的数组
<script type="text/javascript">
//<![CDATA[
var ar=new Array('v1', 'v2', 'v3', ['v41', 'v42']);
for(var i=0; i<ar.length; i++){
document.write(ar[i].toString()+'<br/>');
}
//]]>
</script>
26.0.4 创建数组中的对象
<script type="text/javascript">
//<![CDATA[
var ar=new Array('v1', 'v2', 'v3', {x:'v41', y:'v42'});
for(var i=0; i<ar.length; i++){
if(typeof(ar[i])=='string')
document.write(ar[i]+'<br/>');
else if(typeof(ar[i])=='object'){
document.write('object<br/>');
for(var j in ar[i]){
document.write('obj: '+j+' obj val '+ar[i][j]+'<br/>');
}
}
}
//]]>
</script>
26.1 [array].push(), [array].pop()
<script type="text/javascript">
//<![CDATA[
var $array=new Array('a', 'b', 'c', 'd', 'e')
with(document){
write('source $array.join: '+$array.join()+'<br/>');
write ($array.length+'<br/>');
$array.push(1,1,1,1,1,1,1,1,1,1);
write ('$array.push(1,1,1,1,1,1,1,1,1,1), $array.length: '+$array.length+'<br/>');
write('join $array: '+$array.join()+'<p/>');
write ($array.length+'<br/>');
$array.push(1, 2, 3, 4, 5);
write ('$array.push(1, 2, 3, 4, 5), $array.length: '+$array.length+'<br/>');
write('join $array: '+$array.join()+'<p/>');
write('$array.pop(): '+$array.pop()+'<br/>');
write('$array.length & $array.join(): '+$array.length+' '+$array.join()+'<p/>');
write('$array.pop(10): '+$array.pop(10)+'<br/>');
write('$array.length & $array.join(): '+$array.length+' '+$array.join()+'<br/>');
}
//]]>
</script>
26.2 数组排序
<script type="text/javascript">
//<![CDATA[
var a=new Array();
for (var i=0, j=1; i<10;a[i]=j, i++, j++);
document.write('<h2>未排序前:</h2>');
document.write(a.join());
document.write('<h2>无条件排序:</h2>');
document.write(a.sort().join());
temp=a.sort(function(a, b){return a-b});
document.write('<h2>a-b 排序:</h2>');
document.write(temp.join());
temp=a.sort(function(a, b){return b-a});
document.write('<h2>b-a 排序:</h2>');
document.write(temp.join());
//]]>
</script>
26.3 创建数组指定维数, 从 1 开始.
<script type="text/javascript">
//<![CDATA[
var a=new Array(3);
document.write((a.length+'').bold()+'<br/>');
for(var i=0; i<a.length; i++){
document.write(i+'<br/>');
}
//]]>
</script>
25. toString
25.1 使用 toString 列出数组中的元素
<script type="text/javascript">
//<![CDATA[
var $array=new Array('a', 'a1', 'a2');
alert($array.toString());
//]]>
</script>
24. object
24.1 创建简单对象
<script type="text/javascript">
//<![CDATA[
var $obj=new Object();
$obj={$title:"object example", $date:Date()}
alert($obj.$date);
//]]>
</script>
24.1.1 创建简单对象 一
<script type="text/javascript">
//<![CDATA[
var cnt=new Object();
cnt.title='title this';
cnt.content='content this'
cnt.date='the publishing date of '+Date();
document.write('title: '+cnt.title+'<br/>cnt.content: '+cnt.content+'<br/>cnt.date: '+cnt.date);
//]]>
</script>
24.1.2 创建简单对象 二
<script type="text/javascript">
//<![CDATA[
var cnt={
title:'title this',
content:'content this',
date:'the publishing date of '+Date()
}
document.write('title: '+cnt.title+'<br/>cnt.content: '+cnt.content+'<br/>cnt.date: '+cnt.date);
//]]>
</script>
24.2 创建嵌套对象
<script type="text/javascript">
//<![CDATA[
var cnt={
title:{
headertitle:'header title',
subtitle:'subtitle this'
},
content:'content this',
date:'the publishing date of '+new Date().toLocaleString()
}
document.write('title: '+cnt.title.headertitle.bold().fontcolor('red')+
'<br/>cnt.title.subtitle: '+cnt.title.subtitle.fontcolor('blue')+
'<br/>cnt.content: '+cnt.content.fontcolor('goldenrod')+
'<br/>cnt.date: '+cnt.date);
//]]>
</script>
24.2.1 创建嵌套对象 1
<script type="text/javascript">
//<![CDATA[
var o=new Object();
o.title=' this title ';
o.content=' this content';
o.lve=new Object();
o.lve.title=' this o.lve title';
o.lve.content=' this o.lve content';
document.write('o.title: '+o.title.bold()+'<br/>');
document.write('o.content: '+o.content.bold()+'<br/>');
document.write('o.lve.title: '+o.lve.title.bold()+'<br/>');
document.write('o.lve.content: '+o.lve.content.bold()+'<br/>');
//]]>
</script>
24.3 删除对象中的属性
<script type="text/javascript">
//<![CDATA[
var $obj=new Object();
$obj={$title:"object example", $date:Date()}
//alert($obj.$date);
var $name="";
for(name in $obj)$name+=name+'\n';
alert($name);
delete $obj.$date
var $name="";
for(name in $obj)$name+=name+'\n';
alert($name);
//]]>
</script>
24.4 遍历对象中的属性名
<script type="text/javascript">
//<![CDATA[
var $obj=new Object();
$obj={$title:"object example", $date:Date()}
//alert($obj.$date);
var $name="";
for(name in $obj)$name+=name+'\n';
alert($name);
//]]>
</script>
24.4.1 遍历对象中的属性名 1
<script type="text/javascript">
//<![CDATA[
var o=new Object();
o.title=' this title ';
o.content=' this content';
o.lve=new Object();
o.lve.title=' this o.lve title';
o.lve.content=' this o.lve content';
for (var i in o){
if(typeof o[i]!=='object'){
document.write('object o, element: '+i.fontcolor('red')+' value: '+o[i].bold()+'<br/>');
} else {
document.write('object '+i+' element<br/>');
for(var j in o[i]){
document.write('subobject element :'+j.fontcolor('red')+
' subobject value: '+o[i][j].bold()+'<br/>');
}
}
}
//]]>
</script>
24.5 obj.propertyIsEnumerable('ele')
<script type="text/javascript">
//<![CDATA[
var d=new Date();
d.x='test';
var s=new String();
var o=new Object();
var f=new Function('thest')
document.write(d.propertyIsEnumerable('x'));
document.write(d.propertyIsEnumerable('y'));
//]]>
</script>
24.6 obj.hasOwnProperty('ele')
<script type="text/javascript">
//<![CDATA[
var d=new Date();
d.x='test';
var s=new String();
var o=new Object();
var f=new Function('thest')
document.write(d.hasOwnProperty('x'));
document.write(d.hasOwnProperty('y'));
//]]>
</script>
23. call, apply
23.1 apply
23.1.1 找出数组中最大的数
<script type="text/javascript">
//<![CDATA[
$array=new Array(2, 9, 12, 33, 2, 4444, 22)
var $temp=Math.max.apply(null, $array)
alert($temp)
//]]
</script>
22. break, continue
22.1 continue
<script type="text/javascript">
//<![CDATA[
for (var $i=0; $i<10; $i++){
if($i==5){continue;}
document.write ($i+'<br/>')
}
//]]>
</script>
22.2 break
22.2.1 break 标签
<script type="text/javascript">
//<![CDATA[
//document.write('<xmp>');
outerloop:
for (var i=0; i<10; i++){
document.writeln(('outerloop:'+i).bold()+'<br/>')
innerloop:
for(var j=0; j<10; j++){;
if(i==5)break outerloop;
if(j==9)break innerloop;
document.writeln(('innerloop: '+j).fontcolor('blue')+'<br/>');
}
}
//document.write('</xmp>');
//]]>
</script>
21. with
21.1 简单 with
<script type="text/javascript">
//<![CDATA[
with(document){
write('ok');
}
//]]>
</script>
21.1 简单with (另一写法)
var $dw=document
$dw.write('ok this a test');
20. try, catch, finally
20.1 简单 try, catch
try{
5*kkk
}
catch(e){
alert(e)
}
20.1.1 简单 try, catch 1
<script type="text/javascript">
//<![CDATA[
document.write('<h2>window object:</h2>');
for(var i in window){
try{
document.write(i.bold()+' '+(window[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
//]]>
</script>
19. for in
19.1 简单 for in
<script type="text/javascript">
//<![CDATA[
/* document.write('<h2>top object:</h2>');
for(var i in top){
try{
document.write(i.bold()+' '+(top[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
document.write('<h2>parent object:</h2>');
for(var i in parent){
try{
document.write(i.bold()+' '+(parent[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
document.write('<h2>screen object:</h2>');
for(var i in screen){
try{
document.write(i.bold()+' '+(screen[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
*/
try{
document.write('<h2>clipboardData object:</h2>');
for(var i in clipboardData){
try{
document.write(i.bold()+' '+(clipboardData[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
} catch(ex) {
document.write((ex+'').fontcolor('red'));
}
document.write('<h2>window object:</h2>');
for(var i in window){
try{
document.write(i.bold()+' '+(window[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
/*
document.write('<h2>Option object:</h2>');
for(var i in Option){
try{
document.write(i.bold()+' '+(Option[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
*/
document.write('<h2>frames object:</h2>');
for(var i in frames){
try{
document.write(i.bold()+' '+(frames[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
/*
document.write('<h2>self object:</h2>');
for(var i in self){
try{
document.write(i.bold()+' '+(self[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
*/
document.write('<h2>document object:</h2>');
for(var i in document){
document.write(i.bold()+' '+(document[i]+'').fontcolor('blue')+'<br/>');
}
document.write('<h2>history object:</h2>');
for(var i in history){
try{
document.write(i.bold()+' '+(history[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
/*
document.write('<h2>Image object:</h2>');
for(var i in Image){
try{
document.write(i.bold()+' '+(Image[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
*/
document.write('<h2>navigator object:</h2>');
for(var i in navigator){
try{
document.write(i.bold()+' '+(navigator[i]+'').fontcolor('blue')+'<br/>');
} catch (e) {
document.write(i.fontcolor('red').bold()+': ');
document.write(e.description.fontcolor('red')+'<br/>');
}
}
document.write('<h2>location object:</h2>');
for(var i in location){
document.write(i.bold()+' '+(location[i]+'').fontcolor('blue')+'<br/>');
}
//]]>
</script>
19.1.1 简单 for in 1
for (var $i in window){
document.write($i+'<br/>');
}
19.2 for in 赋值 [数组]
var $array=new Array();
var i=0;
for ($array[i++] in window){
//document.write($i+'<br/>');
}
alert($array[0]);
19.2.1 for in 赋值 [数组] 1
<script type="text/javascript">
//<![CDATA[
var o={a:'aaa', b:'bbb', c:'ccc'};
var a=new Array();
var i=0;
for(a[i++] in o)document.write(a[i-1]);
//for(i in a)document.write(a[i]);
//]]>
</script>
18. for
18.1 简单 for
for (var $i=0; $i<10; $i++) {
document.write($i)
}
18.2 简单 for 1
for (var $i=0, $j=10; $i<10; $i++, $j--) {
document.write(($i*$j)+'<br/>')
}
18.3 循环列出从 a - z 的字母
<script type="text/javascript">
//<![CDATA[
for(var $i='a'.charCodeAt(); $i<='z'.charCodeAt(); $i++){
document.write(String.fromCharCode($i)+'<br/>')
}
//]]>
</script>
18.3 n阶乘
<script type="text/javascript">
//<![CDATA[
var $fN=10
for (var $i=1, $j=1; $i<=$fN; $i++, $j*=$i){
if($i==$fN){document.write($j);}
}
//]]>
</script>
18.4 Fibonacci Numbers
<script type="text/javascript">
//<![CDATA[
for(var $i=0, $j=1, $k=0, $fbcc=0; $i<50; $i++){
document.write($i+'='+$fbcc+'<br/>');
$fbcc=$j+$k;
$j=$k;
$k=$fbcc;
}
//]]>
</script>
17. do while
17.1 简单 do while
var $count=0
do{
document.write($count)
} while(++$count<10)
17.1.2 简单 do while
var $count=1
do{
document.write($count)
} while($count++<10)
16. while
16. 简单 while
var $count=0
while($count<10){ document.write($count);$count++;}
15 if 判断
15.1 简单 if 判断
function ubbTag(fId, str){
document.getElementById(fId).content.focus();
var strEnd=str.replace(/\[/ig,'[/')
if (strEnd.indexOf('=')>-1){ strEnd=strEnd.replace(/(.*?)\=.*?\]/,'$1]') }
if((document.selection)&&(document.selection.type== "Text")){
var oStr=document.selection.createRange();
oStr.text=str+oStr.text+strEnd
} else {
document.getElementById(fId).content.value+=str+strEnd
}
}
15.1.1 简单 if 判断 2
<script type="text/javascript">
//<![CDATA[
var i=0, j=1;
i>j?j+=i:i+=j;
document.write(i+' '+j);
//]]>
</script>
15.1.2 简单 if 判断 3
<script type="text/javascript">
//<![CDATA[
if(!cdti||cdti=='')var cdti='test this';
document.write(cdti);
//]]>
</script>
15.2 if 判断的 三个 写法
<script type="text/javascript">
//<![CDATA[
var a=b=5, c=6
if(a==b)document.write('a equal b <br/>');
(a==b)&&document.write('a equal b <br/>');
a==b?document.write('a equal b <br/>'):'';
//]]>
</script>
15.3 判断执行文件使用网络还是使用本地协议
<script type="text/javascript">
//<![CDATA[
if(location.protocol=='file:'){
alert('local')
} else alert('internet');
//]]>
</script>
15.4 if...else 写法
<script type="text/javascript">
//<![CDATA[
//var i=0
var i=1
if(i==0)document.write('i=0');
else document.write('i!=0');
//]]>
</script>
14. switch
14.1 简单 switch
/* switch(strEnd){
case '\[\/html]' :strEnd=strEnd.replace(/\\[\/,'HTML 和 JS 代码支持[');break;
case '\[\/code]' :strEnd=strEnd.replace(/\\[\/,'代码[');break;
case '\[\/quote]' :strEnd=strEnd.replace(/\\[\/,'引用[');break;
case '\[\/cite]' :strEnd=strEnd.replace(/\\[\/,'引用[');break;
case '\[\/linenum]' :strEnd=strEnd.replace(/\\[\/,'显示行号[');break;
case '\[\/b]' :strEnd=strEnd.replace(/\\[\/,'粗体[');break;
case '\[\/i]' :strEnd=strEnd.replace(/\\[\/,'叙体[');break;
case '\[\/u]' :strEnd=strEnd.replace(/\\[\/,'下划线[');break;
case '\[\/flash]' :strEnd=strEnd.replace(/\\[\/,'Flash 动画[');break;
case '\[\/sound]' :strEnd=strEnd.replace(/\\[\/,'背景声音[');break;
case '\[\/mms]' :strEnd=strEnd.replace(/\\[\/,'WM格式流数据[');break;
case '\[\/rtsp]' :strEnd=strEnd.replace(/\\[\/,'Real格式流数据[');break;
case '\[\/ra]' :strEnd=strEnd.replace(/\\[\/,'在线Real Player播放音频文件[');break;
case '\[\/real]' :strEnd=strEnd.replace(/\\[\/,'Real Player 播放视频文件[');break;
case '\[\/wm]' :strEnd=strEnd.replace(/\\[\/,'在线Windows Media Player播放视频文件[');break;
case '\[\/wma]' :strEnd=strEnd.replace(/\\[\/,'在线Windows Media Player播放音频文件[');break;
case '\[\/iframe]' :strEnd=strEnd.replace(/\\[\/,'插入网页[');break;
} */
13. 时间操作
13.1 以毫秒为单位的倒计时跳转, 来源 CSDN
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<script type="text/javascript">
//<![CDATA[
var go=20000;
var timer=null;
var endTime = new Date().getTime() + go ;
function interval()
{
var n=(endTime-new Date().getTime())/1000;
if(n<0) return;
document.getElementById("jumpTo").innerHTML = n.toFixed(3);
setTimeout(interval, 10);
}
window.onload=function(){
timer=setTimeout("window.location.href='/'", go);
interval();
}
//]]>
</script>
<span id="jumpTo">20.000</span> 秒后 将自动</span>跳转到
12. 随机数
12.1 生成 GUID
<!--start 12.1-->
<html>
<!-- DW6 -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Untitled Document</title>
<script>
function fGuid()
{
var g ="";
for(var i = 0; i < 32; i++)
g += Math.floor(Math.random() * 0xF).toString(0xF) + (i == 8 || i == 12 || i == 16 || i == 20 ? "-" : "");
alert(g.toUpperCase());
}
</script>
</head>
<body onLoad="fGuid();">
</body>
</html>
<!--end 12.1-->
12.1.1 生成 GUID 2
<!--start 12.1.1 -->
<html>
<!-- DW6 -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Untitled Document</title>
<script>
function fGuid() {
var g ="";
for(var i = 0; i < 32; i++)
g += Math.floor(Math.random() * 0xF).toString(0xF) + (i == 8 || i == 12 || i == 16 || i == 20 ? "-" : "");
//alert(g.toUpperCase());
return g.toUpperCase();
}
</script>
</head>
<body>
<form name="form1" method="post" action="">
<input name="textfield" type="text" onMouseMove="this.value=fGuid();" size="50">
</form>
</body>
</html>
<!--end 12.1.1 -->
11.1 检测字符串中是否出现某字符
<script>
function test(str) {
if(str.indexOf("|")>0) {
alert("have |")
}
}
</script>
<input type="text" value="kklskldflksd|ksdkfksjd" onMouseOver="test(this.value)" />
11. 字符串
10.2 鼠标移过选择表单项
onMouseOver="focus();select();"
10.1 单击鼠标右击关闭窗口 (我用左手)
<html onmousedown='window.close();'>
10. 接收鼠标事件
9. 正则表达式
function rbr() {
re=/\<br\/\>*/ig
document.all.textarea.value=document.all.textarea.value.replace(re,"")
}
8. 顯示頁面所有元素
<script language="JavaScript" type="text/javascript">
//<![CDATA[
for(var i in document) {
document.write(i +"="+ document[i]+"<br/>")
}
//]]>
</script>
7. 文本框回车链接
<script>
<!--
function ckKeyPress(jumpto){
if(window.event.keyCode==13) {
window.location.href="?"+jumpto
}
}
//-->shawl.qiu script
</script>
转到:<input type='text' onmousemove='this.focus();this.select();' onkeypress="ckKeyPress(this.value);" />
6. IE 全屏显示
<script language="JavaScript">
<!--
self.moveTo(0,0)
self.resizeTo(screen.availWidth,screen.availHeight)
//-->
</script>
5. 双击拷贝文本
<script LANGUAGE="JAVASCRIPT">
function ClipBoard(tdObj) { //IE Only
var holdtext = document.all['holdtext'];
holdtext.innerText = tdObj.innerText;
Copied = holdtext.createTextRange();
Copied.execCommand("Copy");
alert("text copied");
}
</script>
<form NAME="form1" METHOD="post" ACTION="">
<textarea id="holdtext" style="display:none" ROWS="10"></textarea>
</form>
4. 控制图片大小
<img src="images/teach/opera/01.jpg" onload="javascript:if(this.width>500)this.width=500;" >
//如果图片宽度大于 500px, 则 更改宽度为 500px
3.1 Javascript 结合 Asp 使用数组
<% '连接数据库
set rs=server.CreateObject("adodb.recordset") '创建 rs 数据查询
rs.open "Select a.*, b.* FROM ctglossarysubcat AS a INNER JOIN ctglossarysupercat AS b ON a.gcid = b.gcid order by a.gcid",MM_conn_string,1
%>
<script LANGUAGE="JAVASCRIPT">
var onecount; //定义子类计数
onecount=0; //设置子类计数默认值为0
subcat = new Array(); //定义显示子类数组
<% count = 0
do while not rs.eof %>
subcat[<%=count%>] = new Array("<%=rs("gscat")%>","<%=rs("a.gcid")%>","<%=rs("gscid")%>");
<% count = count + 1
rs.movenext
loop
%>
onecount=<%=count%>; //子类条目总数
</script>
<%
rs.close '关闭 rs 连接
set rs=nothing
%>
3. 数组/Array
2.2 实时显示更改的图片链接
<input type="text" name="" value="<%response.write siteicon %>" onkeyup="javascript:document.all.siteicon.src=(this.value);" /> <img src="<%response.write siteicon %>" alt="<%response.write sitename %>" id="siteicon" />
2.1 按任何键关闭窗口
<body onKeyPress="self.close()">
2. 接收键盘事件
1.6 鼠标经过自动提交表单
onMouseOut="submit()"
1.5.1 鼠标经过时选中,并隐藏原框的文字, 移开再显示文字 ——文本框
<input NAME="findtext" TYPE="text" ID="findtext" value="查找" onMouseOver="this.focus();this.value=''" onMouseOut="this.value='查找';this.select()">
<!-- shawl.qiu script -->
1.5 鼠标经过时选中 ——复选框 Focus()
<input type="checkbox" onMouseOver="checked='true'" />
<!-- shawl.qiu script -->
1.4 Prompt
function prompter()
{
urlLink=window.prompt("请输入链接"," http:// ")
text = window.prompt("链接名")
if(text!="")
document.formT.content.value+=""+text+""
}
1.3 最原始也最实用的 UBB 代码输入方法——SCRIPT & FORM
<form name="formT" id="formT" method="post" action="">
<input type="button" value="url" onclick="this.form.content.value+=''"/>
<input type="button" value="code" onclick="this.form.content.value+='
CODE:'" />
<input type="button" value="quote" onclick="this.form.content.value+='
QUOTE:
'"/>
<br />
<textarea name="content" cols="60" rows="10"></textarea>
<br />
<input type="submit" name="Submit" value="Submit" />
<input type="reset" name="Reset" value="Reset" />
</form>
<!-- shawl.qiu script -->
1.2 确认按钮
<script LANGUAGE="JavaScript">
<!--//确认框, 注意表单名; 按钮属性, 按钮名字不能为 submit
function confirmer()
{
if (confirm("现在提交?")) {
document.formT.submit()
}
else {
document.formT.reset()
}
}gggg
//Script By Shawl.qiu
//-->
</script>
<form name="formT" method="post" action="t1.asp">
<input type="text" name="textfield" value="确认后提交">
<input type="button" name="confbuton" value="提交" onclick="confirmer();">
</form>
1.1 前进后退按钮
<input TYPE="button" VALUE="后退" ONCLICK="history.back(-1)">
<input TYPE="button" VALUE="前进" ONCLICK="history.back(+1)">
1. 按钮
0. 语法
0.1 Switch
function kP() {
switch(event.keyCode) {
case 27: //按 ESC 键关闭窗口.
window.close()
break;
//case 120: //F9 转到主页
//window.location.href="/"
//break;
default:
break;
}
}
-1. 运算符
-1.1 -- 与 ++
<script type="text/javascript">
//<![CDATA[
var x;
x=0;
document.write('x=0, x++: '+(x++)); // 执行 x 后, x 再加 1
x=0;
document.write('<br/>x=0, ++x: '+(++x)); // 执行 x 前, x 先加 1
x=2;
document.write('<br/>x=2, x--: '+(x--)); // 执行 x 后, x 再减 1
x=2;
document.write('<br/>x=2, --x: '+(--x)); // 执行 x 前, x 先减 1
//]]>
</script>
-1.1.1
<script type="text/javascript">
//<![CDATA[
var i=1;
j=++i;
document.write(i); //2
document.write('<br/>');
document.write(j); //2
document.write('<br/>');
var k=1
l=k++
document.write(k); //2
document.write('<br/>');
document.write(l); //1
//]]>
</script>
-1.2 类型转换
<script type="text/javascript">
//<![CDATA[
document.write('100'+100); //'100100' 字符串与数字相加
document.write('<br/>');
document.write('100'-0); //100 转字符串为数值
document.write('<br/>');
document.write(100+''); //'100' 数值转字符串
document.write('<br/>');
document.write(!!100); //true 转布尔值
document.write('<br/>');
document.write(!100); //false 转布尔值
document.write('<br/>');
//]]>
</script>
-1.3 0/0=?
<script type="text/javascript">
//<![CDATA[
document.write(0/0); //NaN
//]]>
</script>
-1.4 == 与 ===
-1.4.1 NaN
<script type="text/javascript">
//<![CDATA[
document.write(NaN==NaN); //false
document.write(NaN===NaN); //false
//]]>
</script>
-1.4.2 true 等价 1, false 等价 0.
<script type="text/javascript">
//<![CDATA[
document.write(1==true); //true
document.write('<br/>');
document.write(0==false); //true
document.write('<br/>');
//]]>
</script>
-1.5 in 操作符
<script type="text/javascript">
//<![CDATA[
var o={e:'ok', f:'ok'}
document.write('e' in o); // true
document.write('<br/>');
document.write('f' in o); // true
document.write('<br/>');
document.write('j' in o); // false
document.write('<br/>');
document.write('toString' in o); // false
document.write('<br/>');
//]]>
</script>
-2. var 定义变量
-2.1 普通定义变量
<script type="text/javascript">
//<![CDATA[
var i
document.write(i+'<br/>');
var j=1, k=2
document.write(j+k+'<br/>');
for(var l=0; l<10; l++)document.write(l+' ');;
//]]>
</script>
-2.1.1 普通定义变量 1
<script type="text/javascript">
//<![CDATA[
var o={a:'aaa', b:'bbb', c:'ccc'}
for(var i in o){
document.write('object element name: '+i.bold()+' object value: '+o[i].fontcolor('blue')+'<br/>');
}
//]]>
</script>
-2.1.2 普通定义变量 2
<script type="text/javascript">
//<![CDATA[
var i=j=k=l='ok';
document.write(i.bold()+'<br/>');
document.write(j.bold()+'<br/>');
document.write(k.bold()+'<br/>');
document.write(l.bold()+'<br/>');
//]]>
</script>
-2.2 全局变量与局部变量
<script type="text/javascript">
//<![CDATA[
var i='global i';//全局
function t(){
var i='local i'; //局部
document.write(i+'<br/>');
j='global j' //全局
document.write(j+'<br/>');
}
document.write(i+'<br/>');
t();
document.write(i+'<br/>');
document.write(j+'<br/>');
var k='global k'
document.write(k+'<br/>');
function t1(){
k='change global k'
document.write(k+'<br/>');
}
t1();
document.write(k+'<br/>');
//]]>
</script>
-2.3 在函数中使用 var 定义一个变量, 该变量将影响整个函数, 不分先后.
var scope = "global";
function f( ) {
alert(scope); // Displays "undefined", not "global"
var scope = "local"; // Variable initialized here, but defined everywhere
alert(scope); // Displays "local"
}
f( );
-2.4 同时初始化多个变量并赋相同值
<script type="text/javascript">
//<![CDATA[
var i=j=k=l=0;
document.write(i+' '+j+' '+k+' '+l+' ');
//]]>
</script>
-3. 优先级
-3.1 函数比其他代码优先执行
<script type="text/javascript">
//<![CDATA[
document.write((t(10)+'').bold()+'<br/>');
t=10;
document.write((t+'').bold()+'<br/>');
function t(n){
return n*n;
}
//]]>
</script>
---/---------------------------------------------------------
常用参数
3. document
2. location
1. this
---------------------------------
3.3 写出字符串
document.write("<input type='button' value='url' onclick='addcontent('','');'/>");
3.2 document.from
指定 表单域
3.1 document.all.id
查找指定 HTML 页面 ID 或 名字
3. document
2.2 转到特定网页
onClick="location.href=' http:// 127.0.0.1/'"
2.1 单独 location
取页面地址
2. location
1.4 this.height
取高度属性
1.3 this.width
取宽度属性
1.2 this.href
取链接地址
1.1 this.src
取图片地址
1. this
---/---------------------------------------------------------
问题集:
3. return 返回多个值 2006-10-14 14:13:18
2. 理解 setInternal 用法
1. 理解 void 用法
---/---------------------------------------------------------
相关摘要:
24. Keep in mind that the function statement is available in all versions of JavaScript, the Function( ) constructor is available only in JavaScript 1.1 and later, and function literals are available only in JavaScript 1.2 and later. Recall that we said the three functions defined earlier are "more or less" equivalent -- there are some differences between these three techniques for function definition, which we'll consider in Section 11.5.
//JavaScript: The Definitive Guide, 4th Edition -- 7.1.3 Function Literals
2006-10-19 14:35:56
23. The Function( ) constructor expects any number of string arguments. The last argument is the body of the function -- it can contain arbitrary JavaScript statements, separated from each other by semicolons. All other arguments to the constructor are strings that specify the names of the parameters to the function being defined. If you are defining a function that takes no arguments, you simply pass a single string -- the function body -- to the constructor.
//JavaScript: The Definitive Guide, 4th Edition -- 7.1.2 The Function( ) Constructor
2006-10-19 14:16:18
22. Note that ECMAScript v3 does not allow function definitions to appear anywhere; they are still restricted to top-level global code and top-level function code. This means that function definitions may not appear within loops or conditionals, for example.[1] These restrictions on function definitions apply only to function declarations with the function statement. As we'll discuss later in this chapter, function literals (another feature introduced in JavaScript 1.2 and standardized by ECMAScript v3) may appear within any JavaScript expression, which means that they can appear within if and other statements.
//JavaScript: The Definitive Guide, 4th Edition -- 7.1 Defining and Invoking Functions
2006-10-19 14:10:13
21. try and finally can be used together without a catch clause. In this case, the finally block is simply cleanup code that is guaranteed to be executed, regardless of any break, continue, or return statements within the try clause. For example, the following code uses a try/finally statement to ensure that a loop counter variable is incremented at the end of each iteration, even when an iteration terminates abruptly because of a continue statement:
//JavaScript: The Definitive Guide, 4th Edition -- 6.17 try/catch/finally
2006-10-18 19:18:08
20. The continue statement, in both its labeled and unlabeled forms, can be used only within the body of a while, do/while, for, or for/in loop. Using it anywhere else causes a syntax error.
//JavaScript: The Definitive Guide, 4th Edition -- 6.12 continue
2006-10-18 16:03:46
19. The following rules are used to determine whether two values are identical according to the === operator:
If the two values have different types, they are not identical.
If both values are numbers and have the same value, they are identical, unless either or both values are NaN, in which case they are not identical. The NaN value is never identical to any other value, including itself! To check whether a value is NaN, use the global isNaN( ) function.
If both values are strings and contain exactly the same characters in the same positions, they are identical. If the strings differ in length or content, they are not identical. Note that in some cases, the Unicode standard allows more than one way to encode the same string. For efficiency, however, JavaScript string comparison compares strictly on a character-by-character basis, and it assumes that all strings have been converted to a "normalized form" before they are compared. See the "String.localeCompare( )" reference page in the core reference section of this book for another way to compare strings.
If both values are the boolean value true or both are the boolean value false, they are identical.
If both values refer to the same object, array, or function, they are identical. If they refer to different objects (or arrays or functions) they are not identical, even if both objects have identical properties or both arrays have identical elements.
If both values are null or both values are undefined, they are identical.
The following rules are used to determine whether two values are equal according to the == operator:
If the two values have the same type, test them for identity. If the values are identical, they are equal; if they are not identical, they are not equal.
If the two values do not have the same type, they may still be equal. Use the following rules and type conversions to check for equality:
If one value is null and the other is undefined, they are equal.
If one value is a number and the other is a string, convert the string to a number and try the comparison again, using the converted value.
If either value is true, convert it to 1 and try the comparison again. If either value is false, convert it to 0 and try the comparison again.
If one value is an object and the other is a number or string, convert the object to a primitive and try the comparison again. An object is converted to a primitive value by either its toString( ) method or its valueOf( ) method. The built-in classes of core JavaScript attempt valueOf( ) conversion before toString( ) conversion, except for the Date class, which performs toString( ) conversion. Objects that are not part of core JavaScript may convert themselves to primitive values in an implementation-defined way.
Any other combinations of values are not equal.
As an example of testing for equality, consider the comparison:
"1" == true
This expression evaluates to true, indicating that these very different-looking values are in fact equal. The boolean value true is first converted to the number 1, and the comparison is done again. Next, the string "1" is converted to the number 1. Since both numbers are now the same, the comparison returns true.
When the equality operator in JavaScript 1.1 attempted to convert a string to a number and failed, it displayed an error message noting that the string could not be converted, instead of converting the string to NaN and returning false as the result of the comparison. This bug has been fixed in JavaScript 1.2.
//JavaScript: The Definitive Guide, 4th Edition -- 5.4 Equality Operators
2006-10-16 21:56:30
18. In top-level code (i.e., JavaScript code that is not part of a function), you can use the JavaScript keyword this to refer to the global object. Within functions, this has a different use, which is described in Chapter 7.
//JavaScript: The Definitive Guide, 4th Edition -- 4.6 Variables as Properties
2006-10-16 16:08:34
17. Garbage collection is automatic and is invisible to the programmer. You can create all the garbage objects you want, and the system will clean up after you! You need to know only enough about garbage collection to trust that it works; you don't have to wonder about where all the old objects go. For those who aren't satisfied, however, Section 11.3, contains further details on the JavaScript garbage-collection process.
//JavaScript: The Definitive Guide, 4th Edition -- 4.5 Garbage Collection
2006-10-16 16:01:55
16. Primitive Types and Reference Types
var a = [1,2,3]; // Initialize a variable to refer to an array
var b = a; // Copy that reference into a new variable
a[0] = 99; // Modify the array using the original reference
alert(b); // Display the changed array [99,2,3] using the new reference
If this result does not seem surprising to you, you're already well familiar with the distinction between primitive and reference types. If it does seem surprising, take a closer look at the second line. Note that it is the reference to the array value, not the array itself, that is being assigned in this statement. After that second line of code, we still have only one array object; we just happen to have two references to it.
//JavaScript: The Definitive Guide, 4th Edition -- 4.4 Primitive Types and Reference Types
15. 在任何情况下,如果六个月以后您还能毫不费力地阅读和理解所编写的代码,则说明这些代码写得不错。
//Windows 脚本技术 -- JScript -- 什么是 JScript?
2006-10-16 14:12:55
14. The rule that all variables declared in a function are defined throughout the function can cause surprising results. The following code illustrates this:
var scope = "global";
function f( ) {
alert(scope); // Displays "undefined", not "global"
var scope = "local"; // Variable initialized here, but defined everywhere
alert(scope); // Displays "local"
}
f( );
//JavaScript: The Definitive Guide, 4th Edition -- 4.3 Variable Scope
13. Variable Scope
The scope of a variable is the region of your program in which it is defined. A global variable has global scope -- it is defined everywhere in your JavaScript code. On the other hand, variables declared within a function are defined only within the body of the function. They are local variables and have local scope. Function parameters also count as local variables and are defined only within the body of the function.
Within the body of a function, a local variable takes precedence over a global variable with the same name. If you declare a local variable or function parameter with the same name as a global variable, you effectively hide the global variable. For example, the following code prints the word "local":
var scope = "global"; // Declare a global variable
function checkscope( ) {
var scope = "local"; // Declare a local variable with the same name
document.write(scope); // Use the local variable, not the global one
}
checkscope( ); // Prints "local"
//JavaScript: The Definitive Guide, 4th Edition -- 4.3 Variable Scope
2006-10-16 1:11:59
12. In general, functions do not know what variables are defined in the global scope or what they are being used for. Thus, if a function uses a global variable instead of a local one, it runs the risk of changing a value upon which some other part of the program relies. Fortunately, avoiding this problem is simple: declare all variables with var
//JavaScript: The Definitive Guide, 4th Edition -- 4.3 Variable Scope
2006-10-15 22:23:32
11. If you attempt to read the value of an undeclared variable, JavaScript will generate an error. If you assign a value to a variable that you have not declared with var, JavaScript will implicitly declare that variable for you. Note, however, that implicitly declared variables are always created as global variables, even if they are used within the body of a function. To prevent the creation of a global variable (or the use of an existing global variable) when you meant to create a local variable for use within a single function, you must always use the var statement within function bodies. It's best to use var for all variables, whether global or local. (The distinction between local and global variables is explored in more detail in the next section.)
//JavaScript: The Definitive Guide, 4th Edition -- 4.2.1 Repeated and Omitted Declarations
2006-10-15 22:00:53
10. Error Objects
ECMAScript v3 defines a number of classes that represent errors. The JavaScript interpreter "throws" an object of one of these types when a runtime error occurs. (See the throw and try statements in Chapter 6 for a discussion of throwing and catching errors.) Each error object has a message property that contains an implementation-specific error message. The types of predefined error objects are Error, EvalError, RangeError, ReferenceError, SyntaxError, TypeError, and URIError. You can find out more about these classes in the core reference section of this book.
//JavaScript: The Definitive Guide, 4th Edition -- 3.11 Error Objects
2006-10-15 19:39:08
9. undefined
Another special value used occasionally by JavaScript is the undefined value returned when you use either a variable that has been declared but never had a value assigned to it, or an object property that does not exist. Note that this special undefined value is not the same as null.
Although null and the undefined value are distinct, the == equality operator considers them to be equal to one another. Consider the following:
my.prop == null
//JavaScript: The Definitive Guide, 4th Edition -- 3.8 undefined
2006-10-15 18:02:39
8. The way to really learn a new programming language is to write programs with it.
//JavaScript: The Definitive Guide, 4th Edition -- 1.10 Exploring JavaScript
2006-10-14 2:40:02
7. Both Netscape and Microsoft have made their JavaScript interpreters available to companies and programmers who want to embed them in their applications. Netscape's interpreter was released as open source and is now available through the Mozilla organization (see http://www.mozilla.org/js/ ). Mozilla actually provides two different versions of the JavaScript 1.5 interpreter. One is written in C and is called "SpiderMonkey." The other is written in Java and, in a flattering reference to this book, is called "Rhino."
//JavaScript: The Definitive Guide, 4th Edition -- 1.4 JavaScript in Other Contexts
2006-10-14 1:13:44
6. 11.1.2 Explicit Type Conversions
Table 11-1 listed the automatic data type conversions that JavaScript performs. It is also possible to explicitly convert values from one type to another. JavaScript does not define a cast operator as C, C++, and Java do, but it does provide similar facilities for converting data values.
As of JavaScript 1.1 (and the ECMA-262 standard), Number( ) , Boolean( ), String( ), and Object( ) may be called as functions as well as being invoked as constructors. When invoked in this way, these functions attempt to convert their arguments to the appropriate type. For example, you could convert any value x to a string with String(x) and convert any value y to an object with Object(y).
There are a few other tricks that can be useful for performing explicit conversions. To convert a value to a string, concatenate it with the empty string:
var x_as_string = x + "";
To force a value to a number, subtract zero from it:
var x_as_number = x - 0;
And to force a value to boolean, use the ! operator twice:
var x_as_boolean = !!x;
Because of JavaScript's tendency to automatically convert data to whatever type is required, explicit conversions are usually unnecessary. They are occasionally helpful, however, and can also be used to make your code clearer and more precise.
//JavaScript: The Definitive Guide, 4th Edition -- 11.1 Data Type Conversion
2006-10-12 12:36:23
5. Each RegExp object has five properties. The source property is a read-only string that contains the text of the regular expression. The global property is a read-only boolean value that specifies whether the regular expression has the g flag. The ignoreCase property is a read-only boolean value that specifies whether the regular expression has the i flag. The multiline property is a read-only boolean value that specifies whether the regular expression has the m flag. The final property is lastIndex, a read-write integer. For patterns with the g flag, this property stores the position in the string at which the next search is to begin. It is used by the exec( ) and test( ) methods, as described in the previous section.
//JavaScript: The Definitive Guide, 4th Edition -- 10.3.2 RegExp Instance Properties
2006-10-9 21:23:26
4. the RegExp constructor. search( ) does not support global searches -- it ignores the g flag of its regular expression argument.
//JavaScript: The Definitive Guide, 4th Edition -- 10.2 String Methods for Pattern Matching
2006-10-9 19:56:40
3. We've seen the . operator used to access the properties of an object. It is also possible to use the [] operator, which is more commonly used with arrays, to access these properties. Thus, the following two JavaScript expressions have the same value:
object.property
object["property"]
//JavaScript: The Definitive Guide, 4th Edition -- 8.6 Objects as Associative Arrays
2006-10-9 14:45:13
2. The typeof Operator
typeof is a unary operator that is placed before its single operand, which can be of any type. Its value is a string indicating the data type of the operand.
The typeof operator evaluates to "number", "string", or "boolean" if its operand is a number, string, or boolean value. It evaluates to "object" for objects, arrays, and (surprisingly) null. It evaluates to "function" for function operands and to "undefined" if the operand is undefined.
//JavaScript: The Definitive Guide, 4th Edition -- 5.10.2 The typeof Operator
1. JavaScript strings (and JavaScript arrays, as we'll see later) are indexed starting with zero.
---/---------------------------------------------------------
小小心得
1. 花括弧定义 对象 元素, 方括弧定义 数组 元素. 2006-10-15 17:55:50
2. Javascript 正则表达式摘要
linenum
Javascript 与正则表达式 By shawl.qiu
语法方法:
5. str.split()
<script type="text/javascript">
//<![CDATA[
var str=' this , is, a, text';
document.write(str.split(/\s*,\s*/));
document.write('<br/>');
document.write(str.split(/\s*,\s*/).join());
//]]>
</script>
4. str.match()
<script type="text/javascript">
//<![CDATA[
var str=' This is a test. ';
document.write(str.match(/\w+/).join());
document.write('<br/>');
document.write(str.match(/\w+/g).join());
//]]>
</script>
3. str.replace()
<script type="text/javascript">
//<![CDATA[
var str=' This is a test. ';
document.write(str.replace(/^(\s+)|(\s+)$/,'----------'));
document.write('<br/>');
document.write(str.replace(/^(\s+)|(\s+)$/g,'----------'));
//]]>
</script>
2. str.search()
<script type="text/javascript">
//<![CDATA[
var str=' This is a test. ';
document.write(str.search(/this/i));
//]]>
</script>
1. 子匹配
<script type="text/javascript">
//<![CDATA[
var str=' this is a test '
document.write(str.match(/(is+).*?\1/)[0]);
//]]>
</script>
0. 创建正则表达式模式
0.1 new RegExp()
<script type="text/javascript">
//<![CDATA[
var str=' this is a test '
var re=new RegExp('\\w+','g');
document.write(str.match(re));
//]]>
</script>
-1. re.exec(str)
<script type="text/javascript">
//<![CDATA[
var str=' this is a test '
var pt=/this|test/g;
var report
while((report=pt.exec(str))!=null){
document.write(('match: ').bold()+report[0].fontcolor('red')+'<br/>');
document.write(('match index: ').bold()+(report.index+'').fontcolor('red')+'<br/>');
document.write(('match lastIndex: ').bold()+(pt.lastIndex+'').fontcolor('red')+'<p/>');
}
//]]>
</script>
-2. re.test(str)
<script type="text/javascript">
//<![CDATA[
var str=' this is a test ';
var re=/\d+/;
document.write(re.test(str));
var re=/\w+/;
document.write(re.test(str));
//]]>
</script>
---/----------------------------------------
摘要:
4. The String methods search( ) , replace( ), and match( ) do not use the lastIndex property as exec( ) and test( ) do. In fact, the String methods simply reset lastIndex( ) to 0. If you use exec( ) or test( ) on a pattern that has the g flag set and you are searching multiple strings, you must either find all the matches in each string, so that lastIndex is automatically reset to zero (this happens when the last search fails), or you must explicitly set the lastIndex property to 0 yourself. If you forget to do this, you may start searching a new string at some arbitrary position within the string rather than from the beginning. Finally, remember that this special lastIndex behavior occurs only for regular expressions with the g flag. exec( ) and test( ) ignore the lastIndex property of RegExp objects that do not have the g flag.
//JavaScript: The Definitive Guide, 4th Edition -- 10.3.1 RegExp Methods for Pattern Matching
2006-10-20 18:10:36
3. match method
The match( ) method is the most general of the String regular expression methods. It takes a regular expression as its only argument (or converts its argument to a regular expression by passing it to the RegExp( ) constructor) and returns an array that contains the results of the match. If the regular expression has the g flag set, the method returns an array of all matches that appear in the string. For example:
"1 plus 2 equals 3".match(/\d+/g) // returns ["1", "2", "3"]
//JavaScript: The Definitive Guide, 4th Edition -- 10.2 String Methods for Pattern Matching
2006-10-20 17:23:08
2. search method
Strings support four methods that make use of regular expressions. The simplest is search( ). This method takes a regular expression argument and returns either the character position of the start of the first matching substring, or -1 if there is no match. For example, the following call returns 4:
"JavaScript".search(/script/i);
If the argument to search( ) is not a regular expression, it is first converted to one by passing it to the RegExp constructor. search( ) does not support global searches -- it ignores the g flag of its regular expression argument.
//JavaScript: The Definitive Guide, 4th Edition -- 10.2 String Methods for Pattern Matching
1. A number of punctuation characters have special meanings in regular expressions. They are:
^ $ . * + ? = ! : | \ / ( ) [ ] { }
//JavaScript: The Definitive Guide, 4th Edition -- 10.1 Defining Regular Expressions