javascript有两种定显示器， setTimeout和setInterval，下面简要介绍两个函数然后附上简单的例子。
setTimeout(function, time) , 当定位到time间隔则执行function函数，执行一次就不再执行
clearTimeout(t), 结束setTimeout定时器
setInterval(function, time), 每隔time间隔执行一次function函数
clearInterval(t),结束setinterval定时器
示例：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>JS Test</title>
<style type="text/css">
.xxm {
color:green;
font:size=36px;
font-weight:bold;
font-family:Microsoft YaHei;
background-color:white
background-position:top center;
}
</style>
</head>
<body>
<p class="xxm">定时器</p>
<script type="text/javascript">
var c1 = 0;
var c2 = 0;
var t;
var t2;
var t3;
function timeCount(){
document.getElementById('txt').value = c1;
c1 = c1 + 1;
t = setTimeout("timeCount()", 1000); //此处实现timeCount函数每隔1s执行一次的功能
}
function stopTimeout(){
clearTimeout(t);
}
function timeCount2(){
document.getElementById('txt').value=c2;
c2=c2+1;
}
function interval(){
t2 = setInterval("timeCount2()", 1000);
}
function stop(){
clearInterval(t2);
}
function startTime(){
var today = new Date();
var y = today.getFullYear();
var mon= today.getMonth();
var day = today.getDate();
var h = today.getHours();
var m = today.getMinutes();
var s = today.getSeconds();
m = checkTime(m);
s = checkTime(s);
document.getElementById('txt').value = y+"-"+mon+"-"+day+" "+h+":"+m+":"+s;
//t3 = setTimeout('startTime()',1000);
}
function start(){
t3 = setInterval('startTime()',1000);
}
function stopTime(){
//clearTimeout(t3);
clearInterval(t3);
}
function checkTime(i){
if (i<10){
i = "0"+i;
}
return i;
}
</script>
<input type="text" id="txt"/><br><br>
<input type="button" value="开始setTimeout事件" onclick="javascript:timeCount()"/>
<input type="button" value="结束setTimeout事件" onclick="javascript:stopTimeout()"/><br><br>
<input type="button" value="开始setInterval事件" onclick="javascript:interval()"/>
<input type="button" value="结束setInterval事件" onclick="javascript:stop()"/><br><br>
<p class="xxm">实时时钟<p/>
<input type="button" value="开始时间" onclick="javascript:start()"/>
<input type="button" value="结束时间" onclick="javascript:stopTime()"/><br><br>
</body>
</html>
示例效果：
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原文：http://blog.csdn.net/xxm524/article/details/46848625
