完全CSS下拉菜单，只用CSS，纯CSS构筑！

</li>
</ul>
</td></tr></table>
<!--[if lte IE 6]>
</a>
<![endif]-->
</li>
</ul>
</div>

</style>
<![endif]-->

<style type="text/css">
.menu {
font-family: verdana, sans-serif;
width:750px;
position:relative;
font-size:0.85em;
padding-bottom:250px;
}
.menu ul {
padding:0;
margin:0;
list-style-type: none;
}
.menu ul li {
float:left;
position:relative;
}
.menu ul li a,安全可视化普及系列一：你的网站安全吗, .menu ul li a:visited {
display:block;
text-decoration:none;
color:#000;
width:139px;
height:3em;
color:#000;
border:1px solid #fff;
border-width:1px 1px 0 0;
background:#dfc184;
padding-left:10px;
line-height:3em;
}
* html .menu ul li a, .menu ul li a:visited {
width:149px;
w\idth:139px;
}
.menu ul li ul {
display: none;
}
table {
margin:-1px;
border-collapse:collapse;
font-size:1em;
}

/* specific to non IE browsers */
.menu ul li:hover a {
color:#fff;
background:#bd8d5e;
}
.menu ul li:hover ul {
display:block;
position:absolute;
top:3em;
margin-top:1px;
left:0;
width:150px;
}
.menu ul li:hover ul li ul {
display: none;
}
.menu ul li:hover ul li a {
display:block;
background:#faeec7;
color:#000;
height:auto;
line-height:1.2em;
padding:5px 10px;
width:129px
}
.menu ul li:hover ul li a.drop {
background:#c9c9a7;
}
.menu ul li:hover ul li a:hover {
background:#c9c9a7;
color:#000;
}
.menu ul li:hover ul li:hover ul {
display:block;
position:absolute;
left:150px;
top:0;
width:150px;
}
.menu ul li:hover ul li:hover ul.left {
left:-150px;
}
</style>
<!--[if lte IE 6]>
<style type="text/css">
.menu ul li a:hover {
color:#fff;
background:#bd8d5e;
}
.menu ul li a:hover ul {
display:block;
position:absolute;
top:3em;
left:0;
background:#fff;
margin-top:0;
marg\in-top:1px;
}
.menu ul li a:hover ul li a {
display:block;
background:#dbe4ab;
color:#000;
height:auto;
line-height:1.5em;
padding:5px 10px;
width:150px;
w\idth:129px;
}
.menu ul li a:hover ul li a.drop {
background:#c9c9a7;
}
.menu ul li a:hover ul li a ul {
visibility:hidden;
position:absolute;
height:0;
width:0;
}
.menu ul li a:hover ul li a:hover {
background:#c9c9a7; color:#000;
}
.menu ul li a:hover ul li a:hover ul {
visibility:visible;
position:absolute;
top:0;
color:#000;
left:150px;
}
.menu ul li a:hover ul li a:hover ul.left {
left:-150px;
}

下面再看看XHTML代码，同样要当真懂得。
<div class="menu">
<ul>
<li><a class="drop" href="
<!--[if IE 7]><!-->
</a>
<!--<![endif]-->
<table><tr><td>
<ul>
<li><a href=" title="The zero dollar ads page">zero dollars advertising page</a></li>
<li><a href=" title="Wrapping text around images">,学网站设计必看之设计常识;wrapping text around images</a></li>
<li><a href=" title="Styling forms">styled form</a></li>
<li><a href=" title="Removing active/focus borders">active focus</a></li>
<li><a class="drop" href=" title="Hover/click with no active/focus borders">hover/click with no borders
<!--[if IE 7]><!-->
</a>
<!--<![endif]-->
<table><tr><td>
<ul>
<li><a href=" title="Styling forms">styled form</a></li>
<li><a href=" title="Removing active/focus borders">removing active/focus borders</a></li>
<li><a href=" title="Hover/click with no active/focus borders">hover/click</a></li>
</ul>
</td></tr></table>
<!--[if lte IE 6]>
</a>
<![endif]-->
</li>
<li class="upone"><a href=" title="Multi-position drop shadow">shadow boxing</a></li>
<li><a href=" title="Image Map for detailed information">image map for detailed information</a></li>
<li><a href=" title="fun with background images">fun with background images</a></li>
<li><a href=" title="fade-out scrolling">fade scrolling</a></li>
<li><a href=" title="em size images compared">em image sizes compared</a></li>
</ul>
</td></tr></table>
<!--[if lte IE 6]>
</a>
<![endif]-->
</li>
<li><a href="
<!--[if IE 7]><!-->
</a>
<!--<![endif]-->
<table><tr><td>
<ul>
<li><a href=" title="a coded list of spies">a coded list of spies</a></li>
<li><a href=" title="a horizontal vertical menu">vertical menu</a></li>
<li><a href=" title="an enlarging unordered list">enlarging unordered list</a></li>
<li><a href=" title="an unordered list with link images">link images</a></li>
<li><a href=" title="non-rectangular links">non-rectangular</a></li>
<li><a href=" title="jigsaw links">jigsaw links</a></li>
<li><a href=" title="circular links">circular links</a></li>
</ul>
</td></tr></table>
<!--[if lte IE 6]>
</a>
<![endif]-->
</li>
<li><a href="
<!--[if IE 7]><!-->
</a>
<!--<![endif]-->
<table><tr><td>
<ul>
<li><a href=" title="A drop down menu">drop down menu</a></li>
<li><a href=" title="A cascading menu">cascading menu</a></li>
<li><a href=" title="Using content:">content:</a></li>
<li><a href=" title=":hover applied to a div">mozzie box</a></li>,学用纯CSS打造可折叠树状菜单;
<li><a href=" title="I can build a rainbow">I can build a rainbow with transparent borders</a></li>
<li><a href=" title="Snooker cue">a snooker cue using border art</a></li>
<li><a href=" title="Target Practise">target practise</a></li>
<li><a href=" title="Two tone headings">two tone headings</a></li>
<li><a href=" title="Shadow text">shadow text</a></li>
</ul>
</td></tr></table>
<!--[if lte IE 6]>
</a>
<![endif]-->
</li>
<li><a href="
<!--[if IE 7]><!-->
</a>
<!--<![endif]-->
<table><tr><td>
<ul>,学好网站策划应具备的条件;
<li><a href=" title="Example one">the first example for Internet Explorer</a></li>
<li><a href=" title="Weft fonts">weft fonts</a></li>
<li><a href=" title="Vertical align">vertically aligning text</a></li>
</ul>
</td></tr></table>
<!--[if lte IE 6]>
</a>
<![endif]-->
</li>
<li><a href="
<!--[if IE 7]><!-->
</a>
<!--<![endif]-->
<table><tr><td>
<ul>
<li><a href=" title="colour wheel">a colour wheel using opaque colours</a></li>
<li><a href=" title="a menu using opacity">a menu using opacity</a></li>
<li><a href=" title="partial opacity">partial opacity</a></li>
<li><a href=" title="partial opacity II">partial opacity II</a></li>
<li><a class="drop" href=" title="Hover/click with no active/focus borders">HOVER/CLICK
<!--[if IE 7]><!-->
</a>,学会用好网页自动转向技术;
<!--<![endif]-->
<table><tr><td>
<ul class="left">
<li><a href=" title="Styling forms">styled form</a></li>
<li><a href=" title="Removing active/focus borders">removing active/focus borders</a></li>
<li><a href=" title="Hover/click with no active/focus borders">hover/click</a></li>
</ul>
</td></tr></table>
<!--[if lte IE 6]>
</a>
<![endif]-->

看看CSS代码，要留神认真看，好好研讨哦！