<!DOCTYPE?html>
<html>
<head>
<meta?charset="utf-8">
<title>菜鳥教程(runoob.com)</title>
<script>
????var?x?=?document.getElementsByClassName("example");
????console.log(x.length)//長度為0
</script>
</head>
<body>
<div?class="example">第一?Div?元素?class="example"。</div>
<script>
????var?x?=?document.getElementsByClassName("example");
????console.log(x.length)//長度為1
</script>
</body>
</html>
為什么在head中獲取元素數(shù)組的長度為0，放到body div元素后可以獲取元素數(shù)組長度
jugge
2017-03-08 17:23:58
