<form>表单里面<button>和<input type="button">在onclick上面有区别吗，为什么这里面用<button>调用onclick时候达不到计时的效果？？？
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>计时器</title>
<script type="text/javascript">
var num=0;
function startCount() {
document.getElementById('count').value=num;
num=num+1;
setTimeout("startCount()",1000);
}
</script>
</head>
<body>
<form>
<input type="text" id="count" />
<button onclick="startCount()">开始</button>
<!--<input type="button" value="开始" onclick="startCount()"/>-->
</form>
</body>
</html>
