代码很简单:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<script type="text/javascript">
alert(document.getElementById("yes"));
</script>
</head>
<body>
<div id="yes"></div>
</body>
</html>
script代码在head中还有外联js中弹出来都是null,只有在body里的最下面才弹出来object HTMLDivElement
为什么?