为什么下面的脚本似乎没有运行?我还想要一些关于如何调试 JavaScript 的建议。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Untitled Document</title>
<style type="text/css">
#clickable_div {
width:100px;
height:50px;
background-color:#9c9c9c;
}
* {
margin:0;
padding:0
}
#nav_menu {
width:100px;
height:auto;
background-color:#CCC;
display:none;
}
#wrap {
width:100px
}
</style>
<script src="js/jquery.js"></script>
<SCRIPT LANGUAGE="JAVASCRIPT">
$('#clickable_div').mouseover( function(){
$('#nav_menu').slideDown();})
$('#wrap').mouseleave( function(){
$('#nav_menu').slideUp();});
</script>
<div id='wrap'>
<div id="clickable_div">MENU</div>
<div id="nav_menu">
<ul>
<li id="l1">AAAAA</li>
<li>BBBBB</li>
<li>CCCCC</li>
<li>DDDDD</li>
</ul>
</div>
</div>
</div>
</head>
<body>
</body>
</html>