setInterval()
方法可按照指定的周期（以毫秒计）来调用函数或计算表达式。
setInterval() 方法会不停地调用函数，直到 clearInterval()
被调用或窗口被关闭。
setTimeout只运行一次，也就是说设定的时间到后就触发运行指定代码，运行完后即结束。
下面是setInterval来取货系统当前时间
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<!DOCTYPE HTML><html lang="zh-cn">
<head><meta charset="utf-8"
/>
<meta http-equiv="Content-Language"
content="zh-cn"
/>
<title>获取系统时间</title><meta name="keywords"
content=""
/>
<meta name="description"
content=""
/>
<style type="text/css">
*{ margin: 0px; padding: 0px; font-size:14px; font-family:‘微软雅黑‘;
}.clearfix:after{content:‘.‘;display:block;height:0;clear:both;visibility:hidden}
.clearfix{display:inline-block;}* html .clearfix{height:1%}.clearfix{display:black;}ul li{ list-style:none;
}</style></head><body><script type="text/javascript">
window.onload = function(){showTime();function toDou(num){ if(num<10){
return
‘0‘+num;
}else{
return
‘‘+num;
}
} function showTime(){ var
date = new
Date();
var
Time = $(‘Nowtime‘);
var
str = toDou(date.getFullYear())+‘年‘+toDou(date.getMonth())+‘月‘+toDou(date.getDate())+‘日‘+toDou(date.getHours())+‘时‘+toDou(date.getMinutes())+‘分‘+toDou(date.getSeconds())+‘秒‘;
Time.innerHTML = str;
}setInterval(showTime,1000);}function $(id){ return
document.getElementById(id);
}</script> <p>现在时间：<span id=‘Nowtime‘></span></p>
</body></html> |
下面是用setInterval与clearInterval简单的用法
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<!DOCTYPE HTML><html lang="zh-cn">
<head><meta charset="utf-8"
/>
<meta http-equiv="Content-Language"
content="zh-cn"
/>
<title>setInterval与clearInterval</title><meta name="keywords"
content=""
/>
<meta name="description"
content=""
/>
<style type="text/css">
*{margin: 0px; padding: 0px; font-size:14px; font-family:‘微软雅黑‘;
}.clearfix:after{content:‘.‘;display:block;height:0;clear:both;visibility:hidden}
.clearfix{display:inline-block;}* html .clearfix{height:1%}.clearfix{display:black;}ul li{list-style:none;}</style></head><body><script type="text/javascript">
window.onload = function(){var
oBtn = $(‘btn‘);
var
oBtn1 = $(‘btn1‘);
var
oTxt = $(‘txt‘);
var
i=0;
var
timer = null;
oBtn.onclick = function(){timer = setInterval(function(){i++;oTxt.value = i;if(i==100){
clearInterval(timer);}},1000);}oBtn1.onclick = function(){clearInterval(timer);}}function $(id){return
document.getElementById(id);
}</script> <input type=‘text‘
id=‘txt‘
value=‘0‘><input type=‘button‘
value=‘开始‘
id=‘btn‘><input type=‘button‘
value=‘关闭‘
id=‘btn1‘>
</body></html> |