天晴云开
2015-08-12 10:58
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>计时器</title>
</head>
<script type="text/javascript">
var num=0;
var i;
var start=document.getElementById('start');
var stop=document.getElementById('stop')
start.onclick=function(){
document.getElementById('count').value=num;
num=num+1;
i=setTimeout("startCount()",1000);
}
stop.onclick= function(){
clearTimeout(i);
}
</script>
</head>
<body>
<form>
<input type="text" id="count" />
<input type="button" id="start" value="Start" />
<input type="button" id="stop" value="Stop" />
</form>
</body>
</html>
请问这样为什么不可以?
i=setTimeout("startCount()",1000); 里面startCount() 几个意思?
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>计时器</title>
</head>
</head>
<body>
<form>
<input type="text" id="count" />
<input type="button" id="start" value="Start"/>
<input type="button" id="stop" value="Stop"/>
</form>
</body>
<script type="text/javascript">
var num=0;
var i;
var start=document.getElementById('start');
var stop=document.getElementById('stop');
start.onclick=function(){
document.getElementById('count').value=num;
num=num+1;
i=setTimeout("startCount()",1000);
}
stop.onclick= function(){
clearTimeout(i);
}
</script>
</html>把script部分放到下面来,你执行脚本的时候,html元素可能还没加载到。
var stop=document.getElementById('stop')后面加个分号看下
JavaScript进阶篇
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