<style type="text/css">
<!--

*{margin:0;padding:0;border:0;}
body {
  font-family: arial, 宋体, serif;
font-size:12px;
}

#menu {
   line-height: 24px; list-style-type: none; background:#666;
}

#menu a {
  display: block; width: 80px; text-align:center;
}

#menu a:link {
  color:#666; text-decoration:none;
}
#menu a:visited {
  color:#666;text-decoration:none;
}
#menu a:hover {
  color:#FFF;text-decoration:none;font-weight:bold;
}

#menu li {
  float: left; width: 80px; background:#CCC;
}
#menu li a:hover{
  background:#999;
}
#menu li ul {
  line-height: 27px; list-style-type: none;text-align:left;
  left: -999em; width: 180px; position: absolute; 
}
#menu li ul li{
  float: left; width: 180px;
  background: #F6F6F6; 
}

#menu li ul a{
  display: block; width: 180px;w\idth: 156px;text-align:left;padding-left:24px;
}

#menu li ul a:link {
  color:#666; text-decoration:none;
}
#menu li ul a:visited {
  color:#666;text-decoration:none;
}
#menu li ul a:hover {
  color:#F3F3F3;text-decoration:none;font-weight:normal;
  background:#C00;
}

#menu li:hover ul {
  left: auto;
}
#menu li.sfhover ul {
  left: auto;
}
#content {
  clear: left; 
}

-->
</style>

<script type=text/javascript>
function menuFix() {
  var sfEls = document.getElementById("menu").getElementsByTagName("li");
  for (var i=0; i<sfEls.length; i++) {
    sfEls[i].onmouseover=function() {
    this.className+=(this.className.length>0? " ": "") + "sfhover";
    }
    sfEls[i].onMouseDown=function() {
    this.className+=(this.className.length>0? " ": "") + "sfhover";
    }
    sfEls[i].onMouseUp=function() {
    this.className+=(this.className.length>0? " ": "") + "sfhover";
    }
    sfEls[i].onmouseout=function() {
    this.className=this.className.replace(new RegExp("( ?|^)sfhover\\b"), 

"");
    }
  }
}
window.onload=menuFix;
</script>

<ul id="menu">
<li><a href="#">产品介绍</a>
  <ul>
  <li><a href="#">产品一</a></li>
  <li><a href="#">产品一</a></li>
  </ul>
</li>
<li><a href="#">服务介绍</a>
  <ul>
  <li><a href="#">服务二</a></li>
  <li><a href="#">服务二</a></li>
  <li><a href="#">服务二</a></li>
  </ul>
</li>
<li><a href="#">成功案例</a>
  <ul>
  <li><a href="#">案例三</a></li>
  <li><a href="#">案例</a></li>
  </ul>
</li>
<li><a href="#">关于我们</a>
  <ul>
  <li><a href="#">我们四</a></li>
  <li><a href="#">我们四</a></li>
  </ul>
</li>

<li><a href="#">在线演示</a>
  <ul>
  <li><a href="#">演示</a></li>
  <li><a href="#">演示</a></li>
  <li><a href="#">演示</a></li>
  </ul>
</li>
<li><a href="#">联系我们</a>
  <ul>
  <li><a href="#">联系联系联系</a></li>
  <li><a href="#">联系</a></li>
  </ul>
</li>

</ul>