Javascript:日期对象(Date)的基本用法

本文代码整理自w3school:http://www.w3school.com.cn  

1.获取当前日期:

document.write("Current time: "+new Date());
2.获取时间戳(毫秒):

document.write(new Date().getTime());
3.设置年月日(年为必选,月日为可选):

var d = new Date();
  d.setFullYear(2012,3,16)
  document.write(d);
  document.write("<br/>");
  document.write(d.getTime());
4.返回当前星期几:

document.write(new Date().getDay())

 5.日期对象的比较: 
 

function compareDate(){
    var oneday = new Date();
    oneday.setFullYear(2015,2,26);
    var currentday = new Date();

    if (oneday<currentday){
      alert("before");
    }else{
      alert("after");
    }
  }
效果图:

Javascript:日期对象(Date)的基本用法_第1张图片


示例代码:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta http-equiv="Content-Language" content="zh-cn" />

<title>Javascript 日期对象</title>
<head>
  <style>
    body {background-color:#e6e6e6}
  </style>
</head>

<body onload="startTime()">
  <h3>(一)返回当前的日期</h3>
  <script>
  document.write("Current time: "+new Date());
  </script>

  <h3>(二)返回时间戳(毫秒)</h3>
  <script>
  document.write(new Date().getTime());
  </script>

  <h3>(三)设置年月日</h3>
  <script>
  var d = new Date();
  d.setFullYear(2012,3,16)
  document.write(d);
  document.write("<br/>");
  document.write(d.getTime());
  </script>

  <h3>(四)将当日的日期(根据 UTC)转换为字符串</h3>
  <script>
  var d2 = new Date()
  document.write (d2.toUTCString())
  </script>

  <h3>(五)返回当前星期几</h3>
  <script>
  var d3=new Date()
  var weekday=new Array(7)
  weekday[0]="星期日"
  weekday[1]="星期一"
  weekday[2]="星期二"
  weekday[3]="星期三"
  weekday[4]="星期四"
  weekday[5]="星期五"
  weekday[6]="星期六"

  document.write(weekday[d3.getDay()])
  </script>

  <h3>(六)显示一个时间钟表</h3>
  <p id = "time_text"></p>
  <script>
    function startTime(){
      var today = new Date();
      var y = today.getFullYear();
      var M = today.getMonth()+1;
      var day = today.getDay();

      var h = today.getHours();
      var m = today.getMinutes();
      var s = today.getSeconds();

      m = checkTime(m);
      s = checkTime(s);
      var content = (y+"/"+M+"/"+day+" "+h+":"+m+":"+s).fontsize(6).fontcolor("red");
      document.getElementById("time_text").innerHTML = content;
      setTimeout("startTime()",500);
    }

    function checkTime(i){
      if(i<10){
        return "0"+i;
      }
      return i;
    }
  </script>

  <h3>(七)日期对象的比较</h3>
  <p>2015.3.26与当前时间的关系?</p>
  <button onclick = "compareDate()">比较</button>
  <script>
  function compareDate(){
    var oneday = new Date();
    oneday.setFullYear(2015,2,26);
    var currentday = new Date();

    if (oneday<currentday){
      alert("before");
    }else{
      alert("after");
    }
  }
  </script>
</body>
</html>





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