W3School TIY 亲自试一试！

<html>
<head>
<style>
body{font-family:arial;}
table{background:black;position:absolute;}
a{color:black;text-decoration:none;font:bold}
a:hover{color:#606060}
td.menu{background:lightblue}

table.topnav
{
font-size:80%;
top:0;
left:0;
}

table.menu
{
font-size:100%;
bottom:0;
z-index:-1;

}
</style>
<script type="text/javascript">
var i=0
var intHide

function show()
{
if (i>-100)
	{
	i=i-1
	document.all("menu").style.bottom=i
	}
}

function showmenu()
{
clearInterval(intHide)
intShow=setInterval("show()",10)
}

function hide()
{
if (i<0)
	{
	i=i+1
	document.all("menu").style.bottom=i
	}
}

function hidemenu()
{
clearInterval(intShow)
intHide=setInterval("hide()",10)
}
</script>
</head>
<body>

<table class="topnav" width="150">
 <tr bgcolor="#FF8080">
  <td onmouseover="showmenu()" onmouseout="hidemenu()">
   <a href="/i/eg_landscape.jpg"> MENU</a><br />
   <table class="menu" id="menu" width="100%">
   <tr><td class="menu"><a href="/html/index.asp">HTML</a></td></tr>
   <tr><td class="menu"><a href="/xhtml/index.asp">XHTML</a></td></tr>
   <tr><td class="menu"><a href="/css/index.asp">CSS</a></td></tr>
   <tr><td class="menu"><a href="/xml/index.asp">XML</a></td></tr>
   <tr><td class="menu"><a href="/xsl/index.asp">XSL</a></td></tr>
   </table>
  </td>
 </tr>
</table>

<br />
<p>请把鼠标移动到 MENU 上，就可以看到菜单的选项。</p>

</body>
</html>

W3School TIY Editor