<!DOCTYPE?HTML>
<html>
<head>
<meta?http-equiv="Content-Type"?content="text/html;?charset=utf-8">
<title>計(jì)時(shí)器</title>
</head>
<script?type="text/javascript">
??var?num=0;
??var?i;
??function?startCount(){
????document.getElementById('count').value=num;
????num=num+1;
????i=setTimeout("startCount()",1000);
??}
??function?stopCount(){
??clearTimeout(i);
??}
</script>
</head>
<body>
??<form>
????<input?type="text"?id="count"?/>
????<input?type="button"?value="Start"??onclick="startCount()"/>
????<input?type="button"?value="Stop"?onclick="stopCount()"/>
??</form>
</body>
</html>
2016-04-20
我猜你是覺得i的新值作用域只在第一個(gè)函數(shù)里。JS作用域跟C,C++什么的差別有點(diǎn)大，具體可以查查JS作用域與作用域鏈。
2016-04-03
i=setTimeout("startCount()",1000);這不是賦值