<%@ Page Language="C#" AutoEventWireup="true" CodeFile="NavigateMenu.aspx.cs" Inherits="NavigateMenu" %> <!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 runat="server"> <title>无标题页</title> <script type="text/javascript" src="https://www.jb51.net/JScript.js" ></script> <style type="text/css"> *{ margin: 0px; padding: 0px; border:0px; } #nav{ width: 200px; margin: 0px; padding: 0px; font-size: 14px; line-height: 30px; } #nav li{ width: 180px; padding-left: 20px; padding-bottom: 1px; list-style-image: none; list-style-type: none; background-color: #FFFFFF; float: left; } #nav a{ padding-left: 20px; background-color: #BFBFBF; display: block; text-decoration: none; } #nav a:hover { background-color: #FF9175; } #nav li ul{ padding-top: 1px; list-style-image: none; list-style-type: none; } #nav li li{ padding-left: 0px; } #nav ul a{ background-color: #EBEBEB; } .cx { display:none; visibility:hidden; } .ex { display:inherit; visibility:inherit; } </style> <script type="text/javascript" > window.onload=function() { statUp(); } </script> </head> <body> <form runat="server"> <div> <ul> <li><a href="javascript:void(0);">菜单1</a> <ul> <li><a href="javascript:void(0);">菜单1_1</a></li> <li><a href="javascript:void(0);">菜单1_2</a></li> </ul> </li> <li><a href="javascript:void(0);">菜单2</a> <ul> <li><a href="javascript:void(0);">菜单2_1</a></li> <li><a href="javascript:void(0);">菜单2_2</a></li> </ul> </li> <li><a href="javascript:void(0);">菜单3</a> <ul> <li><a href="javascript:void(0);">菜单3_1</a></li> <li><a href="javascript:void(0);">菜单3_2</a></li> </ul> </li> </ul> </div> </form> </body> </html>
js文件：
function doMenu(obj){ var items=obj.parentNode.getElementsByTagName("ul"); var itmUl; if(items.length>0){ itmUl=items[0]; } if(itmUl.className!="ex"){ cxAll(); itmUl.className="ex"; }else{ itmUl.className="cx"; } } function statUp(){ cxAll(); } function cxAll(){ var ulDom=document.getElementById("nav"); var items=ulDom.getElementsByTagName("ul"); for (var i=0;i<items.length;i++) { items[i].className="cx"; } }
在这里需要注意的是延迟加载的问题，由于页面加载时需要执行预处理操作statUp()方法，js单独写成一个文件或 js写在<head>节点中时，需要使用window.onload=function(){执行语句;} 延迟加载，不然引用DOM中对象时，会出现缺少对象 错误提示。
别一种解决方法，直接将所有javaScript 写在</html>
<!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=gb2312" /> <title>菜单</title> <script type="text/javascript" src="https://www.jb51.net/Untitled-3.js"></script> <style> *{ margin: 0px; padding: 0px; border:0px; } #nav{ width: 200px; margin: 0px; padding: 0px; font-size: 14px; line-height: 30px; } #nav li{ width: 180px; padding-left: 20px; padding-bottom: 1px; list-style-image: none; list-style-type: none; background-color: #FFFFFF; float: left; } #nav a{ padding-left: 20px; background-color: #BFBFBF; display: block; text-decoration: none; } #nav a:hover { background-color: #FF9175; } #nav li ul{ padding-top: 1px; list-style-image: none; list-style-type: none; } #nav li li{ padding-left: 0px; } #nav ul a{ background-color: #EBEBEB; } .cx { display:none; visibility:hidden; } .ex { display:inherit; visibility:inherit; } </style> </head> <body> <div> <ul> <li><a href="javascript:void(0);">菜单1</a> <ul> <li><a href="javascript:void(0);">菜单1_1</a></li> <li><a href="javascript:void(0);">菜单1_2</a></li> </ul> </li> <li><a href="javascript:void(0);">菜单2</a> <ul> <li><a href="javascript:void(0);">菜单2_1</a></li> <li><a href="javascript:void(0);">菜单2_2</a></li> </ul> </li> <li><a href="javascript:void(0);">菜单3</a> <ul> <li><a href="javascript:void(0);">菜单3_1</a></li> <li><a href="javascript:void(0);">菜单3_2</a></li> </ul> </li> </ul> </div> </body> </html> <script type="text/javascript"> function doMenu(obj){ var items=obj.parentNode.getElementsByTagName("ul"); var itmUl; if(items.length>0){ itmUl=items[0]; } if(itmUl.className!="ex"){ cxAll(); itmUl.className="ex"; }else{ itmUl.className="cx"; } } function statUp(){ cxAll(); //var ulDom=document.getElementById("nav"); //var items=ulDom.getElementsByTagName("ul"); } function cxAll(){ var ulDom=document.getElementById("nav"); var items=ulDom.getElementsByTagName("ul"); for (var i=0;i<items.length;i++) { items[i].className="cx"; } } statUp(); </script>