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Introduction to the principles and examples of countdown in javascript (code)

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Release: 2018-09-01 10:51:40
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This article brings you an introduction to the principles and examples of countdown in JavaScript (code). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Countdown principle: future time point - present time point // present time point (changing) var iNow = new Date();
// future time point (unchanged)

//下面两种方法都可以定义未来的时间点
// var iNew = new Date( 2013, 10, 27,  21,56,0  );

var iNew = new Date( 'November 27,2013 22:3:0' );

// 数字形式:new Date( 2013,4,1,9,48,12 );
// 字符串形式:new Date('June 10,2013 12:12:12');

// January、February、March、April、May、June、
// July、August、September、October、November、December
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var t = Math.floor((iNew - iNow)/1000); Divide by 1000 to convert milliseconds into seconds. Because decimals may appear, round down to integer

// days :Math.floor(t/86400) How many days is the difference between the future time and the present time
// Hours: Math.floor(t�400/3600) How many hours is the difference between the future time and the present time
// Minutes: Math.floor (t�400600/60) How many minutes is the difference between the future time and the present time
// seconds: t` How many seconds is the difference between the future time and the present time

Countdown example:

<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>无标题文档</title>
<style>
.t1 { width:400px; }
</style>
<script>

/*
var t =  Math.floor( new Date().getTime()/1000 );
alert( Math.floor(t/86400)+&#39;天&#39;+Math.floor(t%86400/3600)+&#39;时&#39;+Math.floor(t%86400%3600/60)+&#39;分&#39;+t%60+&#39;秒&#39; );
*/

window.onload = function () {
	var aInp = document.getElementsByTagName(&#39;input&#39;);
	var iNow = null;
	var iNew = null;
	var t = 0;
	var str = &#39;&#39;;
	var timer = null;
	
	aInp[2].onclick = function () {
		iNew = new Date(aInp[0].value);
		clearInterval( timer );
		
		timer = setInterval (function (){
			
			iNow = new Date();
			t = Math.floor( ( iNew - iNow ) / 1000 );
			
			if ( t >= 0 ) {
				
				str = Math.floor(t/86400)+&#39;天&#39;+Math.floor(t%86400/3600)+&#39;时&#39;+Math.floor(t%86400%3600/60)+&#39;分&#39;+t%60+&#39;秒&#39;;
			
				aInp[1].value = str;
				
			} else {
				
				clearInterval( timer );
				
			}
		
		}, 1000);
	};
};
</script>
</head>

<body>

距离:<input class="t1" type="text" value="November 27,2013 22:3:0" /><br />
还剩:<input class="t1" type="text" />
<input type="button" value="开始倒计时吧" />

</body>
</html>
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