程序没响应
<!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" />
</form>
</body>
<script type="text/javascript">
var num=0;
function startCount() {
document.getElementById('count').value=num;
num=num+1;
setTimeout(startCount,1000);
}
startCount();
</script>
</html>
JS 放到 html 后面，可以正常运行，
js 放在上面，没响应了，JS与控件关联，必须要放到控件后面吗？
<!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;
function startCount() {
document.getElementById('count').value=num;
num=num+1;
setTimeout(startCount,1000);
}
startCount();
</script></head>
<body>
<form>
<input type="text" id="count" />
</form>
</body>
</html>
