<!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。