為什么直接調(diào)用函數(shù)不行？
<!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;
??function?startCount()?{
????document.getElementById('count').value=num;
????num=num+1;
????setTimeout("startCount()",1000);??
??}
??startCount();//直接調(diào)用這個(gè)函數(shù)為什么不行啊？一定要用兩次延時(shí)
</script>
</head>
<body>
<form>
<input?type="text"?id="count"?/>
</form>
</body>
</html>
2015-02-28
<input?type="text"?id="count"?/> 這個(gè)都還沒加載，document.getElementById('count')取不到