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  • JavaScript就这么回事(转)

         有些时候你精通一门语言,但是会发现你其实整天在和其它语言打交道,也许你以为这些微不足道,不至于影响你的开发进度,但恰恰是这些你不重视的东西会浪费你很多时间,我一直以为我早在几年前就已经精通JavaScript了,直到目前,我才越来越觉得JavaScript远比我想象的复杂和强大,我开始崇拜它,就像崇拜所有OOP语言一样~
    趁着节日的空隙,把有关JavaScript的方法和技巧整理下,让每个在为JavaScript而烦恼的人明白,JavaScript就这么回事!并希望JavaScript还可以成为你的朋友,让你豁然开朗,在项目中更好的应用~

    适合阅读范围:对JavaScript一无所知~离精通只差一步之遥的人
    基础知识:HTML

    1 创建脚本块

    程序代码
    <script language=”JavaScript”>
    JavaScript 代码写在这里面
    </script>


    2 隐藏脚本代码
     
    程序代码
    <script language=”JavaScript”>
    <!--
    document.write(“Hello”);
    // -->
    </script>

    在不支持JavaScript的浏览器中将不执行相关代码

    3 浏览器不支持的时候显示
     
    程序代码
    <noscript>
    Hello to the non-JavaScript browser.
    </noscript>


    4 链接外部脚本文件
     
    程序代码
    <script language=”JavaScript” src="/”filename.js"”></script>


    5 注释脚本
     
    程序代码
    // This is a comment
    document.write(“Hello”); // This is a comment
    /*
    All of this
    is a comment
    */


    6 输出到浏览器
     
    程序代码
    document.write(“<strong>Hello</strong>”);


    7 定义变量
     
    程序代码
    var myVariable = “some value”;


    8 字符串相加
     
    程序代码
    var myString = “String1” + “String2”;


    9 字符串搜索
     
    程序代码
    <script language=”JavaScript”>
    <!--
    var myVariable = “Hello there”;
    var therePlace = myVariable.search(“there”);
    document.write(therePlace);
    // -->
    </script>


    10 字符串替换
     
    程序代码
    thisVar.replace(“Monday”,”Friday”);


    11 格式化字串
     
    程序代码
    <script language=”JavaScript”>
    <!--
    var myVariable = “Hello there”;
    document.write(myVariable.big() + “<br>”);
    document.write(myVariable.blink() + “<br>”);
    document.write(myVariable.bold() + “<br>”);
    document.write(myVariable.fixed() + “<br>”);
    document.write(myVariable.fontcolor(“red”) + “<br>”);
    document.write(myVariable.fontsize(“18pt”) + “<br>”);
    document.write(myVariable.italics() + “<br>”);
    document.write(myVariable.small() + “<br>”);
    document.write(myVariable.strike() + “<br>”);
    document.write(myVariable.sub() + “<br>”);
    document.write(myVariable.sup() + “<br>”);
    document.write(myVariable.toLowerCase() + “<br>”);
    document.write(myVariable.toUpperCase() + “<br>”);
    var firstString = “My String”;
    var finalString = firstString.bold().toLowerCase().fontcolor(“red”);
    // -->
    </script>


    12 创建数组
     
    程序代码
    <script language=”JavaScript”>
    <!--
    var myArray = new Array(5);
    myArray[0] = “First Entry”;
    myArray[1] = “Second Entry”;
    myArray[2] = “Third Entry”;
    myArray[3] = “Fourth Entry”;
    myArray[4] = “Fifth Entry”;
    var anotherArray = new Array(“First Entry”,”Second Entry”,”Third Entry”,”Fourth Entry”,”Fifth Entry”);
    // -->
    </script>


    13 数组排序
     
    程序代码
    <script language=”JavaScript”>
    <!--
    var myArray = new Array(5);
    myArray[0] = “z”;
    myArray[1] = “c”;
    myArray[2] = “d”;
    myArray[3] = “a”;
    myArray[4] = “q”;
    document.write(myArray.sort());
    // -->
    </script>


    14 分割字符串
     
    程序代码
    <script language=”JavaScript”>
    <!--
    var myVariable = “a,b,c,d”;
    var stringArray = myVariable.split(“,”);
    document.write(stringArray[0]);
    document.write(stringArray[1]);
    document.write(stringArray[2]);
    document.write(stringArray[3]);
    // -->
    </script>


    15 弹出警告信息
     
    程序代码
    <script language=”JavaScript”>
    <!--
    window.alert(“Hello”);
    // -->
    </script>


    16 弹出确认框
     
    程序代码
    <script language=”JavaScript”>
    <!--
    var result = window.confirm(“Click OK to continue”);
    // -->
    </script>


    17 自定义函数
     
    程序代码
    <script language=”JavaScript”>
    <!--
    function multiple(number1,number2) {
    var result = number1 * number2;
    return result;
    }
    // -->
    </script>


    18 调用JS函数
     
    程序代码
    <a href=”#” onClick=”functionName()”>Link text</a>
    <a href="/”javascript:functionName"()”>Link text</a>


    19 在页面加载完成后执行函数
     
    程序代码
    <body onLoad=”functionName();”>
    Body of the page
    </body>


    20 条件判断
     
    程序代码
    <script>
    <!--
    var userChoice = window.confirm(“Choose OK or Cancel”);
    var result = (userChoice == true) ? “OK” : “Cancel”;
    document.write(result);
    // -->
    </script>


    21 指定次数循环
     
    程序代码
    <script>
    <!--
    var myArray = new Array(3);
    myArray[0] = “Item 0”;
    myArray[1] = “Item 1”;
    myArray[2] = “Item 2”;
    for (i = 0; i < myArray.length; i++) {
    document.write(myArray[i] + “<br>”);
    }
    // -->
    </script>


    22 设定将来执行
     
    程序代码
    <script>
    <!--
    function hello() {
    window.alert(“Hello”);
    }
    window.setTimeout(“hello()”,5000);
    // -->
    </script>  


    23 定时执行函数
     
    程序代码
    <script>
    <!--
    function hello() {
    window.alert(“Hello”);
    window.setTimeout(“hello()”,5000);
    }
    window.setTimeout(“hello()”,5000);
    // -->
    </script>


    24 取消定时执行
     
    程序代码
    <script>
    <!--
    function hello() {
    window.alert(“Hello”);
    }
    var myTimeout = window.setTimeout(“hello()”,5000);
    window.clearTimeout(myTimeout);
    // -->
    </script>


    25 在页面卸载时候执行函数
     
    程序代码
    <body onUnload=”functionName();”>
    Body of the page
    </body>


    JavaScript就这么回事2:浏览器输出

    26 访问document对象
     
    程序代码
    <script language=”JavaScript”>
    var myURL = document.URL;
    window.alert(myURL);
    </script>


    27 动态输出HTML
     
    程序代码
    <script language=”JavaScript”>
    document.write(“<p>Here’s some information about this document:</p>”);
    document.write(“<ul>”);
    document.write(“<li>Referring Document: “ + document.referrer + “</li>”);
    document.write(“<li>Domain: “ + document.domain + “</li>”);
    document.write(“<li>URL: “ + document.URL + “</li>”);
    document.write(“</ul>”);
    </script>


    28 输出换行
     
    程序代码
    document.writeln(“<strong>a</strong>”);
    document.writeln(“b”);


    29 输出日期
     
    程序代码
    <script language=”JavaScript”>
    var thisDate = new Date();
    document.write(thisDate.toString());
    </script>


    30 指定日期的时区
     
    程序代码
    <script language=”JavaScript”>
    var myOffset = -2;
    var currentDate = new Date();
    var userOffset = currentDate.getTimezoneOffset()/60;
    var timeZoneDifference = userOffset - myOffset;
    currentDate.setHours(currentDate.getHours() + timeZoneDifference);
    document.write(“The time and date in Central Europe is: “ + currentDate.toLocaleString());
    </script>


    31 设置日期输出格式
     
    程序代码
    <script language=”JavaScript”>
    var thisDate = new Date();
    var thisTimeString = thisDate.getHours() + “:” + thisDate.getMinutes();
    var thisDateString = thisDate.getFullYear() + “/” + thisDate.getMonth() + “/” + thisDate.getDate();
    document.write(thisTimeString + “ on “ + thisDateString);
    </script>


    32 读取URL参数
     
    程序代码
    <script language=”JavaScript”>
    var urlParts = document.URL.split(“?”);
    var parameterParts = urlParts[1].split(“&”);
    for (i = 0; i < parameterParts.length; i++) {
    var pairParts = parameterParts[i].split(“=”);
    var pairName = pairParts[0];
    var pairValue = pairParts[1];
    document.write(pairName + “ :“ +pairValue );
    }
    </script>

    你还以为HTML是无状态的么?

    33 打开一个新的document对象
     
    程序代码
    <script language=”JavaScript”>
    function newDocument() {
    document.open();
    document.write(“<p>This is a New Document.</p>”);
    document.close();
    }
    </script>


    34 页面跳转
     
    程序代码
    <script language=”JavaScript”>
    window.location = “http://www.x-force.cn/”;
    </script>


    35 添加网页加载进度窗口
     
    程序代码
    <html>
    <head>
    <script language='javaScript'>
    var placeHolder = window.open('holder.html','placeholder','width=200,height=200');
    </script>
    <title>The Main Page</title>
    </head>
    <body onLoad='placeHolder.close()'>
    <p>This is the main page</p>
    </body>
    </html>


    JavaScript就这么回事3:图像

    36 读取图像属性
     
    程序代码
    <img src="/”image1.jpg"” name=”myImage”>
    <a href=”# ” onClick=”window.alert(document.myImage.width)”>Width</a>


    37 动态加载图像
     
    程序代码
    <script language=”JavaScript”>
    myImage = new Image;
    myImage.src = “Tellers1.jpg”;
    </script>


    38 简单的图像替换
     
    程序代码
    <script language=”JavaScript”>
    rollImage = new Image;
    rollImage.src = “rollImage1.jpg”;
    defaultImage = new Image;
    defaultImage.src = “image1.jpg”;
    </script>
    <a href="/”myUrl"” onMouseOver=”document.myImage.src = rollImage.src;”
    onMouseOut=”document.myImage.src = defaultImage.src;”>
    <img src="/”image1.jpg"” name=”myImage” width=100 height=100 border=0>


    39 随机显示图像
     
    程序代码
    <script language=”JavaScript”>
    var imageList = new Array;
    imageList[0] = “image1.jpg”;
    imageList[1] = “image2.jpg”;
    imageList[2] = “image3.jpg”;
    imageList[3] = “image4.jpg”;
    var imageChoice = Math.floor(Math.random() * imageList.length);
    document.write(‘<img src=”’ + imageList[imageChoice] + ‘“>’);
    </script>


    40 函数实现的图像替换
     
    程序代码
    <script language=”JavaScript”>
    var source = 0;
    var replacement = 1;
    function createRollOver(originalImage,replacementImage) {
    var imageArray = new Array;
    imageArray[source] = new Image;
    imageArray[source].src = originalImage;
    imageArray[replacement] = new Image;
    imageArray[replacement].src = replacementImage;
    return imageArray;
    }
    var rollImage = createRollOver(“image1.jpg”,”rollImage1.jpg”);
    </script>
    <a href=”#” onMouseOver=”document.myImage1.src = rollImage1[replacement].src;”
    onMouseOut=”document.myImage1.src = rollImage1[source].src;”>
    <img src="/”image1.jpg"” width=100 name=”myImage1” border=0>
    </a>


    41 创建幻灯片
     
    程序代码
    <script language=”JavaScript”>
    var imageList = new Array;
    imageList[0] = new Image;
    imageList[0].src = “image1.jpg”;
    imageList[1] = new Image;
    imageList[1].src = “image2.jpg”;
    imageList[2] = new Image;
    imageList[2].src = “image3.jpg”;
    imageList[3] = new Image;
    imageList[3].src = “image4.jpg”;
    function slideShow(imageNumber) {
    document.slideShow.src = imageList[imageNumber].src;
    imageNumber += 1;
    if (imageNumber < imageList.length) {
    window.setTimeout(“slideShow(“ + imageNumber + “)”,3000);
    }
    }
    </script>
    </head>
    <body onLoad=”slideShow(0)”>
    <img src="/”image1.jpg"” width=100 name=”slideShow”>


    42 随机广告图片
     
    程序代码
    <script language=”JavaScript”>
    var imageList = new Array;
    imageList[0] = “image1.jpg”;
    imageList[1] = “image2.jpg”;
    imageList[2] = “image3.jpg”;
    imageList[3] = “image4.jpg”;
    var urlList = new Array;
    urlList[0] = “http://some.host/”;
    urlList[1] = “http://another.host/”;
    urlList[2] = “http://somewh/ere.else/”;
    urlList[3] = “http://right.here/”;
    var imageChoice = Math.floor(Math.random() * imageList.length);
    document.write(‘<a href=”’ + urlList[imageChoice] + ‘“><img src=”’ + imageList[imageChoice] + ‘“></a>’);
    </script>


    JavaScript就这么回事4:表单

    43 表单构成
     
    程序代码
    <form method=”post” action=”target.html” name=”thisForm”>
    <input type=”text” name=”myText”>
    <select name=”mySelect”>
    <option value=”1”>First Choice</option>
    <option value=”2”>Second Choice</option>
    </select>
    <br>
    <input type=”submit” value=”Submit Me”>
    </form>


    44 访问表单中的文本框内容
     
    程序代码
    <form name=”myForm”>
    <input type=”text” name=”myText”>
    </form>
    <a href='#' onClick='window.alert(document.myForm.myText.value);'>Check Text Field</a>


    45 动态复制文本框内容
     
    程序代码
    <form name=”myForm”>
    Enter some Text: <input type=”text” name=”myText”><br>
    Copy Text: <input type=”text” name=”copyText”>
    </form>
    <a href=”#” onClick=”document.myForm.copyText.value =
    document.myForm.myText.value;”>Copy Text Field</a>


    46 侦测文本框的变化
     
    程序代码
    <form name=”myForm”>
    Enter some Text: <input type=”text” name=”myText” onChange=”alert(this.value);”>
    </form>


    47 访问选中的Select
     
    程序代码
    <form name=”myForm”>
    <select name=”mySelect”>
    <option value=”First Choice”>1</option>
    <option value=”Second Choice”>2</option>
    <option value=”Third Choice”>3</option>
    </select>
    </form>
    <a href='#' onClick='alert(document.myForm.mySelect.value);'>Check Selection List</a>


    48 动态增加Select项
     
    程序代码
    <form name=”myForm”>
    <select name=”mySelect”>
    <option value=”First Choice”>1</option>
    <option value=”Second Choice”>2</option>
    </select>
    </form>
    <script language=”JavaScript”>
    document.myForm.mySelect.length++;
    document.myForm.mySelect.options[document.myForm.mySelect.length - 1].text = “3”;
    document.myForm.mySelect.options[document.myForm.mySelect.length - 1].value = “Third Choice”;
    </script>


    49 验证表单字段
     
    程序代码
    <script language=”JavaScript”>
    function checkField(field) {
    if (field.value == “”) {
    window.alert(“You must enter a value in the field”);
    field.focus();
    }
    }
    </script>
    <form name=”myForm” action=”target.html”>
    Text Field: <input type=”text” name=”myField”onBlur=”checkField(this)”>
    <br><input type=”submit”>
    </form>


    50 验证Select项
     
    程序代码
    function checkList(selection) {
    if (selection.length == 0) {
    window.alert(“You must make a selection from the list.”);
    return false;
    }
    return true;
    }


    51 动态改变表单的action
     
    程序代码
    <form name=”myForm” action=”login.html”>
    Username: <input type=”text” name=”username”><br>
    Password: <input type=”password” name=”password”><br>
    <input type=”button” value=”Login” onClick=”this.form.submit();”>
    <input type=”button” value=”Register” onClick=”this.form.action = ‘register.html’; this.form.submit();”>
    <input type=”button” value=”Retrieve Password” onClick=”this.form.action = ‘password.html’; this.form.submit();”>
    </form>


    52 使用图像按钮
     
    程序代码
    <form name=”myForm” action=”login.html”>
    Username: <input type=”text” name=”username”><br>
    Password: <input type=”password”name=”password”><br>
    <input type=”image” src="/”login.gif"” value=”Login”>
    </form>


    53 表单数据的加密
     
    程序代码
    <SCRIPT LANGUAGE='JavaScript'>
    <!--
    function encrypt(item) {
    var newItem = '';
    for (i=0; i < item.length; i++) {
    newItem += item.charCodeAt(i) + '.';
    }
    return newItem;
    }
    function encryptForm(myForm) {
    for (i=0; i < myForm.elements.length; i++) {
    myForm.elements[i].value = encrypt(myForm.elements[i].value);
    }
    }

    //-->
    </SCRIPT>
    <form name='myForm' onSubmit='encryptForm(this); window.alert(this.myField.value);'>
    Enter Some Text: <input type=text name=myField><input type=submit>
    </form>


    JavaScript就这么回事5:窗口和框架

    54 改变浏览器状态栏文字提示
     
    程序代码
    <script language=”JavaScript”>
    window.status = “A new status message”;
    </script>


    55 弹出确认提示框
     
    程序代码
    <script language=”JavaScript”>
    var userChoice = window.confirm(“Click OK or Cancel”);
    if (userChoice) {
    document.write(“You chose OK”);
    } else {
    document.write(“You chose Cancel”);
    }
    </script>


    56 提示输入
     
    程序代码
    <script language=”JavaScript”>
    var userName = window.prompt(“Please Enter Your Name”,”Enter Your Name Here”);
    document.write(“Your Name is “ + userName);
    </script>


    57 打开一个新窗口
     
    //打开一个名称为myNewWindow的浏览器新窗口
    程序代码
    <script language=”JavaScript”>
    window.open(“http://www.liu21st.com/”,”myNewWindow”);
    </script>


    58 设置新窗口的大小
     
    程序代码
    <script language=”JavaScript”>
    window.open(“http://www.liu21st.com/”,”myNewWindow”,'height=300,width=300');
    </script>


    59 设置新窗口的位置
     
    程序代码
    <script language=”JavaScript”>
    window.open(“http://www.liu21st.com/”,”myNewWindow”,'height=300,width=300,left=200,screenX=200,top=100,screenY=100');
    </script>


    60 是否显示工具栏和滚动栏
     
    程序代码
    <script language=”JavaScript”>
    window.open(“http://www.x-force.cn/",toolbar=no, menubar=no);
    </script>


    61 是否可以缩放新窗口的大小
     
    程序代码
    <script language=”JavaScript”>
    window.open('http://www.x-force.cn/' , 'myNewWindow', 'resizable=yes' );</script>


    62 加载一个新的文档到当前窗口
     
    程序代码
    <a href='#' onClick='document.location = '125a.html';' >Open New Document</a>


    63 设置页面的滚动位置
     
    程序代码
    <script language=”JavaScript”>
    if (document.all) { //如果是IE浏览器则使用scrollTop属性
    document.body.scrollTop = 200;
    } else { //如果是NetScape浏览器则使用pageYOffset属性
    window.pageYOffset = 200;
    }</script>


    64 在IE中打开全屏窗口
     
    程序代码
    <a href='#' onClick=”window.open('http://www.juxta.com/','newWindow','fullScreen=yes');”>Open a full-screen window</a>


    65 新窗口和父窗口的操作
     
    程序代码
    <script language=”JavaScript”>
    //定义新窗口
    var newWindow = window.open(“128a.html”,”newWindow”);
    newWindow.close(); //在父窗口中关闭打开的新窗口
    </script>在新窗口中关闭父窗口
    程序代码
    window.opener.close()


    66 往新窗口中写内容
     
    程序代码
    <script language=”JavaScript”>
    var newWindow = window.open(“”,”newWindow”);
    newWindow.document.open();
    newWindow.document.write(“This is a new window”);
    newWIndow.document.close();
    </script>


    67 加载页面到框架页面
     
    程序代码
    <frameset cols=”50%,*”>
    <frame name=”frame1” src="/”135a.html"”>
    <frame name=”frame2” src="/”about:blank"”>
    </frameset>
    在frame1中加载frame2中的页面
    parent.frame2.document.location = “135b.html”;


    68 在框架页面之间共享脚本
     
    如果在frame1中html文件中有个脚本
    程序代码
    function doAlert() {
    window.alert(“Frame 1 is loaded”);
    }
    那么在frame2中可以如此调用该方法

    程序代码
    <body onLoad=”parent.frame1.doAlert();”>
    This is frame 2.
    </body>


    69 数据公用
     
    可以在框架页面定义数据项,使得该数据可以被多个框架中的页面公用
    程序代码
    <script language=”JavaScript”>
    var persistentVariable = “This is a persistent value”;
    </script>
    <frameset cols=”50%,*”>
    <frame name=”frame1” src="/”138a.html"”>
    <frame name=”frame2” src="/”138b.html"”>
    </frameset>

    这样在frame1和frame2中都可以使用变量persistentVariable


    70 框架代码库
     
    根据以上的一些思路,我们可以使用一个隐藏的框架页面来作为整个框架集的代码库

    程序代码
    <frameset cols=”0,50%,*”>
    <frame name=”codeFrame” src="/”140code.html"”>
    <frame name=”frame1” src="/”140a.html"”>
    <frame name=”frame2” src="/”140b.html"”>
    </frameset>
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  • 原文地址:https://www.cnblogs.com/quanhai/p/1497461.html
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