CSS制作水平导航菜单效果

<script>
startList = function() {
if (document.all&&document.getElementById) {
navRoot = document.getElementById("nav");
for (i=0; i<navRoot.childNodes.length; i++) {
node = navRoot.childNodes[i];
if (node.nodeName=="SPAN") {
node.onmouseover=function() {this.className+=" over";}
node.onmouseout=function() {this.className=this.className.replace(" over", "");}
}
}
}
}
window.onload=startList;
</script>
<style>
body {
  font: normal 11px verdana;
}
div#nav{
  border-left: 1px solid #ccc;
}
span {
  margin: 0px;
  padding: 0px;
  list-style: none;
  width: 120px; /* Width of Menu Items */
  position: relative;
  border: 1px solid #ccc;
  border-left: 0px;
}
span div span {
  border: 1px solid #ccc;
  border-top: 0px;
}
span div {
  position: absolute;
  left: -1px;
  top: 24px; /* Set 1px less than menu width */
  display: none;
}

/* Styles for Menu Items */
div span a {
  width: 100%;
  text-decoration: none;
  color: #777;
  background: #fff; /* IE6 Bug */
  padding: 5px;
}

div span a:hover { color: #E2144A; background: #f9f9f9; } /* Hover Styles */
   
span div span a { padding: 2px 5px; } /* Sub Menu Styles */
   
span:hover div, span.over div { display: inline; } /* The magic */
</style>

<div id="nav">
  <span><a href="#">chinahtml</a>
  <div>
  </div>
  </span>
  <span><a href="#">About</a>
  <div>
    <span><a href="#">History</a></span>
    <span><a href="#">Team</a></span>
    <span><a href="#">Offices</a></span>
  </div>
  </span>
  <span><a href="#">Services</a>
  <div>
    <span><a href="#">Web Design</a></span>
    <span><a href="#">Internet Marketing</a></span>
    <span><a href="#">Hosting</a></span>
    <span><a href="#">Domain Names</a></span>
    <span><a href="#">Broadband</a></span>
  </div>
  </span>
  <span><a href="#">Contact Us</a>
  <div>
    <span><a href="#">United Kingdom</a></span>
    <span><a href="#">France</a></span>
    <span><a href="#">USA</a></span>
    <span><a href="#">Austraspana</a></span>
  </div>
  </span>
</div>