<!DOCTYPE HTML>
<html>
<head>
<title>Scope Chain & Closure Example </title>
<script type="text/javascript">
( function initAnchors(){
var anchor = document.getElementById('anchor1');
alert(anchor); //想了好久才知道为什么总是null
})(); //自执行
</script>
</head>
<body> <h1>Scope Chain & Closure Example</h1> <ul>
<li><a href="#" id="anchor1">Anchor 1</a></li>
<li><a href="#" id="anchor2">Anchor 2</a></li>
<li><a href="#" id="anchor3">Anchor 3</a></li>
</ul> </body> </html>
2.应该改为：
<script type="text/javascript">
function initAnchors(){
var anchor = document.getElementById('anchor1');
alert(anchor);
};
</script>
</head>
<body onload="initAnchors()"> //使用onload事件，以前总是觉得自己不会犯这样的错，直到出错后才会真正记在头脑中。