实现效果：
CSS：
#sddm
{margin: 0 auto;
padding: 0;
z-index: 30;
background-color:#F4F4F4;
width: 480px;
height:23px;}
#sddm li
{margin: 0;
padding: 0;
list-style: none;
float: left;
font: bold 12px arial}
#sddm li a
{display: block;
margin: 0 1px 0 0;
padding: 4px 10px;
width: 60px;
background: #5970B2;
color: #FFF;
text-align: center;
text-decoration: none}
#sddm li a:hover
{background: #49A3FF}
#sddm div
{position: absolute;
visibility: hidden;
margin: 0;
padding: 0;
background: #EAEBD8;
border: 1px solid #5970B2}
#sddm div a
{position: relative;
display: block;
margin: 0;
padding: 5px 10px;
width: auto;
white-space: nowrap;
text-align: left;
text-decoration: none;
background: #EAEBD8;
color: #2875DE;
font: 12px arial}
#sddm div a:hover
{background: #49A3FF;
color: #FFF}
代码详情：
<script type="text/javascript">
<!–
var timeout = 500;
var closetimer= 0;
var ddmenuitem = 0;
// open hidden layer
function mopen(id)
{
// cancel close timer
mcancelclosetime();
// close old layer
if(ddmenuitem) ddmenuitem.style.visibility = ‘hidden’;
// get new layer and show it
ddmenuitem = document.getElementById(id);
ddmenuitem.style.visibility = ‘visible’;
}
// close showed layer
function mclose()
{
if(ddmenuitem) ddmenuitem.style.visibility = ‘hidden’;
}
// go close timer
function mclosetime()
{
closetimer = window.setTimeout(mclose, timeout);
}
// cancel close timer
function mcancelclosetime()
{
if(closetimer)
{
window.clearTimeout(closetimer);
closetimer = null;
}
}
// close layer when click-out
document.onclick = mclose;
// –>
</script>
<ul id="sddm">
<li><a href="#" onmouseover="mopen(‘m1’)" onmouseout="mclosetime()">Home</a>
<div id="m1" onmouseover="mcancelclosetime()" onmouseout="mclosetime()">
<a href="#">HTML DropDown</a>
<a href="#">DHTML DropDown menu</a>
<a href="#">JavaScript DropDown</a>
<a href="#">DropDown Menu</a>
<a href="#">CSS DropDown</a>
</div>
</li>
<li><a href="#" onmouseover="mopen(‘m2’)" onmouseout="mclosetime()">Download</a>
<div id="m2" onmouseover="mcancelclosetime()" onmouseout="mclosetime()">
<a href="#">ASP Dropdown</a>
<a href="#">Pulldown menu</a>
<a href="#">AJAX dropdown</a>
<a href="#">DIV dropdown</a>
</div>
</li>
<li><a href="#" onmouseover="mopen(‘m3’)" onmouseout="mclosetime()">Order</a>
<div id="m3" onmouseover="mcancelclosetime()" onmouseout="mclosetime()">
<a href="#">Visa Credit Card</a>
<a href="#">Paypal</a>
</div>
</li>
<li><a href="#" onmouseover="mopen(‘m4’)" onmouseout="mclosetime()">Help</a>
<div id="m4" onmouseover="mcancelclosetime()" onmouseout="mclosetime()">
<a href="#">Download Help File</a>
<a href="#">Read online</a>
</div>
</li>
<li><a href="#" onmouseover="mopen(‘m5’)" onmouseout="mclosetime()">Contact</a>
<div id="m5" onmouseover="mcancelclosetime()" onmouseout="mclosetime()">
<a href="#">E-mail</a>
<a href="#">Submit Request Form</a>
<a href="" target="_blank">68ecshop.com</a>
</div>
</li>
</ul>
，含泪播种的人一定能含笑收获。
