This article mainly introduces the CSS combined with JS to make the implementation of the Drop-down menu, the need for friends can refer to the following
Code as follows: <% @page pageencoding= "utf-8" contenttype= "Text/html;charset=utf-8"%> <html > <HEAD> <title>WebForm5</title> <style>/* Root = horizontal, Secondary = Vertical */ ul#navmenu-h { margin:0; border:0 none; padding:0; ; /*for khtml*/ list-style:none; height:24px; } ul#navmenu-h Li { margin:0; bo rder:0 none; padding:0; Float:left; /*for gecko*/ display:inline; list-style:none; position:relative; height:24px; Ul#navmenu-h ul { margin:0; border:0 none; padding:0; width:160px; list-style:no ne; display:none; position:absolute; top:24px; left:0; } ul#navmenu-h UL:AF ter/*from IE 7 lack of compliance*/{ clear:both; display:block; font:1px/0px serif; Content: "."; height:0; visibility:hidden; } ul#navmenu-h ul Li { width:160px; float:lef T /*for IE 7 Lack of compliance*/ display:block!important; display:inline; /*for ie*/ } /* Root Menu */ ul#navmenu-h a { border:1px solid #FFF; Border-right-co Lor: #CCC; border-bottom-color: #CCC; padding:0 6px; float:none; /*for opera*/ Float:left; /*for ie*/ display:block; background: #EEE; color: #666; font:bold 10px/22px Verdana, Arial, Hel Vetica, sans-serif; text-decoration:none; height:auto!important; height:1%; /*for ie*/ } /* Root Menu Hover persistence */ ul#navmenu-h a:hover, ul#navmenu-h-Li:hover a, ul#navmenu-h li.iehover A { background: #CCC; color: #FFF; } * 2nd Menu */ Ul#navmenu-h li:hover Li a, ul#navmenu-h li.iehover Li a { float:none; background: #EEE; color: #666; } /* 2nd Menu Hover Persistence * / ul#navmenu-h li:hover li a:hover, ul#navmenu-h li:hover li:hover a, ul#navmenu-h li.iehover li A:hover , ul#navmenu-h li.iehover li.iehover a { background: #CCC; color: #FFF; } /* 3rd Menu */ ul#navmenu-h li:hover li:hover li a, ul#navmenu-h-li.iehover-li.iehover li a { background: #EEE; &nbs P Color: #666; } /* 3rd Menu Hover Persistence */ ul#navmenu-h li:hover li:hover Li a:hover, Ul#navmenu-h li:hover li:hover li:hover a, ul#navmenu-h li.iehover li.iehover li a:hover, ul#navmenu-h Over Li.iehover li.iehover a { background: #CCC; color: #FFF; } /* 4th Menu */ Ul#nav Menu-h li:hover li:hover li:hover li a, -ul#navmenu-h li.iehover-Li.iehover li.iehover li a { background: #EEE; color: #666; &nbSp } /* 4th Menu Hover */ ul#navmenu-h li:hover li:hover li:hover li a:hover, ul#navmenu-h li.iehove R li.iehover Li.iehover li a:hover { background: #CCC; color: #FFF; } ul#navmenu-h ul ul,&n Bsp Ul#navmenu-h ul ul { display:none; position:absolute; top:0; left:160px; } &nbs P /* Do not move-must Come before display:block for Gecko */ ul#navmenu-h li:hover ul ul, ul#navmenu-h li:hove R ul ul ul, Ul#navmenu-h li.iehover ul ul, ul#navmenu-h Li.iehover ul ul { display:none; P Ul#navmenu-h li:hover ul, ul#navmenu-h ul li:hover ul, ul#navmenu-h ul ul Li:hover ul, -H li.iehover ul, ul#navmenu-h ul li.iehover ul, Ul#navmenu-h ul ul Li.iehover ul { display:block;  ; } </style><script language= "javascript" > navhover = function () { var lis = document. GetelemeNtbyid ("Navmenu-h"). getElementsByTagName ("LI"); for (var i=0; i<lis.length; i++) { lis[i].onmouseover= function () { this.classname+= "Iehover"; } lis[i].onmouseout=function () { This.className.replace (New RegExp ("Iehoverb"), ""); } } } if (window.attachevent) Window.attachevent ("onload", Navhover); </script> </HEAD> <body> <ul ID = "Navmenu-h" > <li><a href= "#" >root nav item1</a> <ul> <li><a href= "#" >sub nav item1</a></li> <li><a href= "#" >sub nav item1-2</a></li > </ul> </li> <li><a href= "#" >root nav item2</a> <ul>& nbsp <li><a href= "#" >sub nav item2</a></li> <li><a href= "#" >Sub nav item2-2</ a></li> </ul> </li> <li≫<a href= "#" >root nav item3</a> <ul> <li><a href= "#" >sub nav item3</a ></li> <li><a href= "#" >sub nav item3-2</a></li> </ul> </ li> </ul> </body> </html>