JavaScript 实现天数时分秒倒计时功能详解

parseInt("10"); //返回 10
parseInt("19",10); //返回 19 (10+9)
parseInt("11",2); //返回 3 (2+1)
parseInt("17",8); //返回 15 (8+7)
parseInt("1f",16); //返回 31 (16+15)
parseInt("010"); //未定：返回 10 或 8

<!DOCTYPE html> 
<html> 
<head> 
<meta charset="utf-8" > 
<title>JS实现倒计时(天数,时,分,秒)</title> 
 
</head> 
<body onload="leftTimer()"> 
 
<h2>剩余时间:</h2> 
<div id="timer"></div> 
</body> 
</html> 

<script language="javascript" type="text/javascript"> 
function leftTimer(year,month,day,hour,minute,second){ 
 var leftTime = (new Date(year,month-1,day,hour,minute,second)) - (new Date()); //计算剩余的毫秒数 
 var days = parseInt(leftTime / 1000 / 60 / 60 / 24 , 10); //计算剩余的天数 
 var hours = parseInt(leftTime / 1000 / 60 / 60 % 24 , 10); //计算剩余的小时 
 var minutes = parseInt(leftTime / 1000 / 60 % 60, 10);//计算剩余的分钟 
 var seconds = parseInt(leftTime / 1000 % 60, 10);//计算剩余的秒数 
 days = checkTime(days); 
 hours = checkTime(hours); 
 minutes = checkTime(minutes); 
 seconds = checkTime(seconds); 
 setInterval("leftTimer(2016,11,11,11,11,11)",1000); 
 document.getElementById("timer").innerHTML = days+"天" + hours+"小时" + minutes+"分"+seconds+"秒"; 
} 
function checkTime(i){ //将0-9的数字前面加上0，例1变为01 
 if(i<10) 
 { 
 i = "0" + i; 
 } 
 return i; 
} 
 
</script> 

<html>
<body>
<input type="text" value="" id="date2">
<input type="button" onclick="go(document.getElementById('date2').value);" value="开始">
<div id="timer"></div>
<script type="text/javascript">
 // 倒计时
 var _ordertimer = null;
 var data=new Date();
 document.getElementById("date2").value=data.getFullYear()+'-'+(data.getMonth()+1)+'-'+data.getDate()+' '+data.getHours()+':'+data.getMinutes()+':'+data.getSeconds();//当前时间
 function leftTimer(enddate) {
 var leftTime = (new Date(enddate)) - new Date(); //计算剩余的毫秒数
 var days = parseInt(leftTime / 1000 / 60 / 60 / 24, 10); //计算剩余的天数
 var hours = parseInt(leftTime / 1000 / 60 / 60 % 24, 10); //计算剩余的小时
 var minutes = parseInt(leftTime / 1000 / 60 % 60, 10);//计算剩余的分钟
 var seconds = parseInt(leftTime / 1000 % 60, 10);//计算剩余的秒数
 days = checkTime(days);
 hours = checkTime(hours);
 minutes = checkTime(minutes);
 seconds = checkTime(seconds);
 if (days >= 0 || hours >= 0 || minutes >= 0 || seconds >= 0) document.getElementById("timer").innerHTML = days + "天" + hours + "小时" + minutes + "分" + seconds + "秒";
 if (days <= 0 && hours <= 0 && minutes <= 0 && seconds <= 0) {
 window.clearInterval(_ordertimer);
 _ordertimer = null;
 }
 }
 function checkTime(i) { //将0-9的数字前面加上0，例1变为01
 if (i < 10) {
 i = "0" + i;
 }
 return i;
 }
 function go(v){
 var date1=new Date(),data2=new Date(v);
 if(data2<date1)return;//设置的时间小于现在时间退出
 _ordertimer = setInterval(function(){leftTimer(data2)}, 1000);
 }
 </script>
 </body>
 </html>