JS-Date日期内置对象

1、基本用法

<script>
      var date = new Date();
      document.write(date+"<br/>");//获取具体时间
      
      document.write(date.getFullYear()+"<br/>");//获取年份
      document.write(date.getTime()+"<br/>");//获取1970年至今毫秒数
      date.setFullYear(2010, 1, 1);
      document.write(date+"<br/>");  //自己设置时间
      
   </script>

2、实现简单的时钟操作

 1 <!DOCTYPE html>
 2 <html>
 3 <head>
 4 <meta charset="UTF-8">
 5 <title>uvi</title>
 6      <link rel="stylesheet" href="style.css" type="text/css">
 7 </head>
 8 <body onload="startTime()">
 9    <script>
10       /*  实现简单的时钟操作  */
11       function startTime(){
12           var today = new Date();
13           var h = today.getHours();
14           var m = today.getMinutes();
15           var s = today.getSeconds();
16           m = checkTime(m);
17           s = checkTime(s);
18           document.getElementById("timetxt").innerHTML = h+":"+m+":"+s;
19           t = setTimeout(function(){
20              startTime(); 
21           },500);
22       }
23       function checkTime(i){//如果是个位数，在前面补"0"
24           if(i<10){
25               i="0"+i;
26           }
27           return i;
28       }
29       
30    </script>
31    <div id = "timetxt"></div>
32    
33 </body>
34 </html>