本来想在网上找一些js实例来练练手，结果发现一本书《突破JavaScript编程实例五十讲》，看了下内容还不错，就下了下来；
后面又下了该书籍的源码，一看才发现这本书编的日期是2002年的，代码运行之后，有些代码可以运行，有些代码已经失效，原因是其所用的一些语言是已经淘汰的了。
其次就是由于是很早之前写的，那时候可能还没有css，js,html分离的想法，都是杂糅在一起的，看起来很不舒服。
还有就是，代码末尾都是不带分号的，还有各种不加关键字var的隐性全局变量等，都影响了程序的整洁性，简洁性。
于是就想，要不我把他的代码重新编写，来实现书中的要求。
在此，也对该书的作者马健兵等编著表示致敬，感谢他们的辛苦编著。
由于空间的限制，就不将js,css以单独文件存储了，全部都在html文件中，但已分离。
1、指定位置的时钟显示
时钟始终显示在网页的正中间，12小时制。
效果图：
源代码：
<!doctype html> <html> <head> <meta charset="utf-8"> <title>指定位置的时钟</title> <style> body{ font-size: 30px; font-family: Arial; background: #fef4d9; } #Current-time{ color:#66ff00; font-size: 30px; } #liveclock{ position:absolute; top:50%; left: 50%; width: 250px; height: 100px; margin: -50px 0 0 -125px; } p{ text-align: center; color:#ff00ff; margin: 0px; } </style> </head> <body> <div id="liveclock" > <div id="show"></div> </div> <script > function display() { var Digital=new Date(); var hours=Digital.getHours(); var minutes=Digital.getMinutes(); var seconds=Digital.getSeconds(); var dn="AM"; if(hours>12) //改成12小时制的 { dn="PM"; hours=hours-12; } if(hours==0) hours=12; if(minutes<=9) minutes="0"+minutes; //改成两位数的显示 if(seconds<=9) seconds="0"+seconds; var myclock="<b><p id='Current-time'>Current time is:</p><p>"+hours+":"+minutes+":"+seconds+" "+dn+"</p></b>"; var liveclock=document.getElementById("liveclock"); liveclock.innerHTML=myclock; setTimeout("display()",1000); } display(); </script> </body> </html>
2、表针式时钟
由于书上的代码太老了，看不懂，自己重新写了一份。效果图如下：
源代码：
<!doctype html> <html> <head> <meta charset="utf-8"> <title>表针式时钟</title> <style> body{ background: #fef4d9; } #time{ position: absolute; width: 212px; height: 216px; top:50%; left: 50%; margin: -108px 0 0 -106px; border: 2px solid yellow; } .timeNum{ position: absolute; } #pt0{ position: absolute; top:20px; left: 105px; border: 4px solid red; height: 90px; z-index: 1px; } #pt1{ position: absolute; top:35px; left: 105px; border: 4px solid blue; height: 75px; z-index: 100px; } #pt2{ position: absolute; top:50px; left: 105px; border: 4px solid yellow; height: 60px; z-index: 110px; } </style> </head> <body> <div id="time"> <div id="c0" class="timeNum" > </div> <div id="c1" class="timeNum"><b>1</b></div> <div id="c2" class="timeNum"><b>2</b></div> <div id="c3" class="timeNum"><b>3</b></div> <div id="c4" class="timeNum"><b>4</b></div> <div id="c5" class="timeNum"><b>5</b></div> <div id="c6" class="timeNum"><b>6</b></div> <div id="c7" class="timeNum"><b>7</b></div> <div id="c8" class="timeNum"><b>8</b></div> <div id="c9" class="timeNum"><b>9</b></div> <div id="c10" class="timeNum"><b>10</b></div> <div id="c11" class="timeNum"><b>11</b></div> <div id="c12" class="timeNum"><b>12</b></div> <div id="pt0" > </div> <div id="pt1" ></div> <div id="pt2" ></div> </div> </body> <script language=javascript> function getid(id){ return document.getElementById(id); } //将数字以圆形的形式显示在屏幕上。根据三角函数的计算 function clockNum(){ for (var i=1; i<13;i++){ var c1=getid("c"+i); angle=i*30/360*Math.PI*2; c1.style.top=0+(100-Math.cos(angle)*100)+"px"; c1.style.left=100+Math.sin(angle)*100+"px"; } } function clockRotate(){ //获取当前的时间 var start= new Date(); var H=start.getHours(); var M=start.getMinutes(); var S=start.getSeconds(); //设置其旋转的角度，分针每次6度，秒针每次6度，时针每次0.5度 var mDu=M*6; var hDu=M*0.5+H*30; var sDu=S*6; var pt0=getid("pt0"); var pt1=getid("pt1"); var pt2=getid("pt2"); //设置其绕末端旋转，宽度是在中间，高度是在整个高度的末尾，采用百分数的形式 pt0.setAttribute('style',''+'transform:rotate('+ sDu +'deg); '+'transform-origin: center 93%;'); pt1.setAttribute('style',''+'transform:rotate('+ mDu +'deg); '+'transform-origin: center 94%;'); pt2.setAttribute('style',''+'transform:rotate('+ hDu +'deg); '+'transform-origin: center 95%;'); } //每隔1毫秒检测一次 setInterval(clockRotate,100); function init(){ clockNum(); } init(); </script> </html>
3、带按钮开关的form时钟
采用按钮的形式进行控制，按下开，显示时间和日期，按下关，则清空。效果图如下
源代码：
<!doctype html> <html> <head> <meta charset="utf-8"> <title>带按钮开关的Form时钟</title> <style> body{ background: #aebcdf; } form{ position:absolute; left:50; top:50; z-index:5; } input{ color:red; } input[type="text"]{ color: black; } .center{ position: absolute; top:50%; left: 50%; transform: translate(-50%, -50%); border: 2px solid yellow; width: 220px; height: 42px; padding: 10px; } </style> </head> <body> <div class="center"> <form name="clock" > <input type="text" name="disp" value="" size=30 onFocus="this.blur()" ><br> <input type="button" name="rad" value="off" id="offbtn" >关 <input type="button" name="rad" value=" on" id="onbtn">开 </form> <div> </body> <script> //公共事件 var common={ //获取id getid:function (id){ return document.getElementById(id); }, //绑定事件 on:function (element,eventName,listener){ if (element.addEventListener){ element.addEventListener(eventName,listener,false); } else if (element.attachEvent){ element.attachEvent('on'+eventName,listener); } else element['on'+eventName]=listener; }, } //时间的方法与属性 var time={ //用来标记是开还是关，0表示关 enabled:0, //存储星期 day:["星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"], //设定和显示时间 //注意中间用了toLocaleString(); Time_Set:function () { var today = new Date(); TM=window.setTimeout('time.Time_Set()', 1000); var timeStr=today.toLocaleString()+" "+time.day[today.getDay()]; document.clock.disp.value = timeStr; console.log(today.toLocaleString()); }, } //全局定时函数名字 var TM; //点击开事件 var onbtn=common.getid("onbtn"); common.on(onbtn,'click',function(){ if(time.enabled == 0) { time.Time_Set(); time.enabled = 1; } }); //点击关事件 var offbtn=common.getid("offbtn"); common.on(offbtn,'click',function(){ if( time.enabled==1 ) { document.clock.disp.value=''; clearTimeout( TM ); time.enabled = 0; } }); </script> </html>
4、年龄提示器
网页打开时依次弹出3个输入对话框，分别需要你输入你的出生日期（年月日），然后显示内容，显示你的出生年月，距离下一次你的生日还有多少时间，以及你活了多少时间。效果图：
源代码：
<!doctype html> <html> <head> <meta charset="utf-8"> <title>年龄提示器</title> <style> div{ position: absolute; top:50%; left: 50%; transform:translate(-50%,-50%); width: 375px; height: 200px; border: 2px solid red; padding: 20px; } p{ margin: 0; margin-bottom: 10px; } input{ margin-bottom: 10px; } </style> </head> <body bgcolor="f9fcb6" > <div> <form> <p id="birday"></p> <p id="age"></p> <input type="text" name="nextYear" size="47" value=""> <p>I've been alive for...</p> <input type="text" name="liveYear" size="47" value=""> <p>您已在本站停留了</p> <input type=text name="input1" size=10 value=""> <br> </form> </div> </body> <script > function getid(id){ return document.getElementById(id); } var timerID=window.setTimeout("showtime()",1); //弹出输入框，获取用户的出生日期,注意要把日期转化为数字 var bMonth =parseInt(prompt('Which month were you born in?(月份)','1-12')); var bDate =parseInt(prompt('Which day were you born on?(天)','1-31')); var bYear =parseInt(prompt('Which year were you born in?(年份)','1900-'+new Date().getFullYear())); var tMonth = ['January','February','March','April','May','June','July','August','September','October','November','December']; var corrMonth = tMonth[bMonth-1]; getid("birday").innerHTML=" I was born <b>"+corrMonth+", "+bDate+", "+bYear+"</b>. (<b>"+bMonth+"/"+bDate+"/"+bYear+"</b>)"; //传入格式化后的时间，用来计算两个时间差，nextAgeDay > today function computeTime(nextAgeDay,today){ var day={}; var liveSec=nextAgeDay.getTime(); var lTime = today.getTime(); var daysec=24*60*60*1000; var hoursec=60*60*1000; var minsec=60*1000; var tt=(-lTime+liveSec); //计算时间差，天，小时，分，秒 day._1day=Math.floor(tt/daysec); day._1hour=Math.floor((tt-day._1day*daysec)/hoursec); day._1min=Math.floor((tt-day._1day*daysec-day._1hour*hoursec)/minsec); day._1sec=Math.floor((tt-day._1day*daysec-day._1hour*hoursec-day._1min*minsec)/1000); return day; } //计算距离下一岁还有多少天的时候，可以采用与现在的秒数相减getTime; function showtime() { //获取当前日期 var today = new Date(); var month = today.getMonth() + 1; var date = today.getDate(); var year = today.getFullYear(); //计算下一次生日是哪一年 var nextAgeYear; var yourAge = year - bYear; if (bMonth < month || ((bMonth == month) && (date > bdate))) { yourAge--; nextAgeYear=year+1; } else { nextAgeYear=year; } //下一年几岁 var nextAge = yourAge + 1; //将下一次生日时间格式化，默认时间在00:00;计算距离下一次生日还还有多长时间 var nextAgeDay = new Date(""+nextAgeYear+","+bMonth+", "+bDate+" , 00:00"); var day=computeTime(nextAgeDay,today); //将出生日期时间格式化，默认时间在00:00;计算已经活了多久了 var bornAgeDay = new Date(""+bYear+","+bMonth+", "+bDate+" , 00:00"); var lday=computeTime(today,bornAgeDay); //将结果输出 document.forms[0].nextYear.value =""+day._1day+"days, "+day._1hour+"hours, "+day._1min+"minutes, "+day._1sec+"seconds"; getid("age").innerHTML=" I am <b>"+yourAge+"</b> years old, and will turn <b>"+nextAge+"</b> in:"; document.forms[0].liveYear.value =""+lday._1day+"days, "+lday._1hour+"hours, "+lday._1min+"minutes, "+lday._1sec+"seconds"; timerID = window.setTimeout("showtime()",1000); } //第三个输入框,计算停留时间 var sec=0; var min=0; var hou=0; var idt=window.setTimeout("update();",1); function update() { if(sec==60){sec=0;min+=1;} if(min==60){min=0;hou+=1;} document.forms[0].input1.value=hou+"时"+min+"分"+sec+"秒"; idt=window.setTimeout("update();",1000); sec++; } </script> </html>
5、得到文件的最后修改时间
本节主要讲获取HTML文件的最后修改时间。效果如下，其实跟前面的例子很像。
源代码：
<!doctype html> <html> <head> <meta charset="utf-8"> <title>获得文件的最后修改时间</title> <style> body{ background: yellow; } .center{ position: absolute; top:50%; left: 50%; transform:translate(-50%,-50%); width: 300px; height: 110px; border: 2px solid red; padding: 10px; } p{ text-align: center; margin: 0px; padding: 10px; } </style> </head> <body> <script> //获得文件的格式化最后修改时间 function DocDate() { var StrofLastMod = document.lastModified; //获得文件的最后修改时间，它是一个string类型的变量。 var months = ["January","February","March","April","May","June","July","August", "September","October","November","December"]; //月份名变量，供转换。 var days = ["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"];//星期名变量，供转换 var c = ":"; //用来分隔时，分，秒。 var mdate =new Date(StrofLastMod); var month = months[mdate.getMonth()]; var date = mdate.getDate(); var year = mdate.getFullYear(); var day = days[mdate.getDay()]; var minutes=mdate.getMinutes(); var hours= mdate.getHours(); var seconds=mdate.getSeconds(); var miliSec=mdate.getMilliseconds(); var dateStr = year+" "+month+" "+date+" "+day+" "+hours+c+minutes+c+seconds+"."+miliSec; //获得格式化的文件最后修改时间。 return dateStr; } var div=document.createElement("div"); div.className="center"; var divson=document.createElement("div"); divson.innerHTML="<p>This File is last updated at:</p><p>"+DocDate()+"</p><p>"+document.lastModified+"</p>"; div.appendChild(divson); document.body.appendChild(div); </script> </body> </html>