网页特效----HTML中树的实现方法 - 站长论坛

<!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" xml:lang="en" lang="en">
<head>
  <title>Current Tree Node Opener</title>
  <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
  <link rel="stylesheet" href="tree.css" type="text/css" media="screen" />
  <meta http-equiv="expires" content="-1" />
  <meta http-equiv="pragma" content="no-cache" />
  <meta name="robots" content="none" />
  <meta name="rating" content="all" />
  <meta name="author" content="Bluegrass Technologies" />
  <meta name="email" content="paulw@bluegrassgroup.com" />
  <script language="javascript" type="text/javascript" src="common.js"></script>
</head>
<body onload="showCurrentSection();">
  <ul id="menu">
<li><a href="a.htm">Section 1</a></li>
<li><a href="">Section 2</a>
<ul>
   <li><a href="">Section 2.1</a></li>
   <li><a href="">Section 2.2</a></li>
   <li><a href="">Section 2.3</a>
   <ul id="navcurrentsection">
   <li><a href="">Section 2.3.1</a></li>
   <li><a href="">Section 2.3.2</a></li>
   </ul>
   </li>
   <li><a href="">Section 2.4</a></li>
</ul>
</li>
<li><a href="">Section 3</a></li>
  </ul>
</body>
</html>
下面是树的样式表
tree.css
body
{
font-family: Verdana, Arial, Sans-Serif;
font-size: small;
background-color: #ffffff;
}
ul#menu
{
border: solid 1px #333333;
border-top-width: 15px;
padding: 10px;
padding-top: 6px;
margin: 0px;
width: 200px;
}
ul#menu li
{
margin: 0px;
list-style-type: none;
border: solid 1px #ffffff;
}
ul#menu li ul
{
margin: 0px 0px 0px 15px;
display: none;
}
ul#menu li a
{
background-image: url(closed.gif);
background-repeat: no-repeat;
background-position: 0px 4px;
text-indent: 15px;
display: block;
text-decoration: none;
color: #333333;
}
ul#menu li a:hover
{
color: #000000;
background-color: #eeeeee;
background-image: url(open.gif);
}