代码如下:
<html>
<head><meta http-equiv="content-type" content='text/html;charset=gb18030'>
<style>
*{
margin:0px;
padding:0px;}
body{
font-family:verdana,sans-serif;
font-size:14px;
background:#EFEFEF;
text-align:center;}
#center{
margin:0 auto;
width:980px;
}
#ul1{
list-style-type:none;
margin-left:15px}
#ul1 li{
width:190px;
list-style-type:none;
float:left;
position:relative;
height:40px;
background:#CECECE;
text-align:center;
font-size:20px;
border:1 #F4F4F4 groove;
color:#FFF;
}
#ul1 li ul{
list-style-type:none;
display:none;
position:absolute;
top:40px;
margin-top:1px;
} <!--display:none隐藏导航栏的小导航(即aaaa)-->
#ul1 li ul li{
width:188px;
}
#ul1 li a:link{
display:block;
height:40px;
text-decoration:none;
color:#F7F7F7;
}<!--伪类-->
#ul1 li a:visited{
background:#585858;
}
#ul1 li a:hover{
background:#CCFFCC;
}
</style>
<script>
function display(li){
var dis=li.getElementsByTagName("ul")[0];
dis.style.display="block";
}
function hiddle(li){
var hid=li.getElementsByTagName("ul")[0];
hid.style.display="none";}
</script></head>
<body><div id="center">
<ul id="ul1">
<li onMouseOver="display(this)" onMouseOut="hiddle(this)">number1
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)"> number2
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)" >number3
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)" >number4
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)" >number5
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
</ul>
</div>
</body>
</html>
<html>
<head><meta http-equiv="content-type" content='text/html;charset=gb18030'>
<style>
*{
margin:0px;
padding:0px;}
body{
font-family:verdana,sans-serif;
font-size:14px;
background:#EFEFEF;
text-align:center;}
#center{
margin:0 auto;
width:980px;
}
#ul1{
list-style-type:none;
margin-left:15px}
#ul1 li{
width:190px;
list-style-type:none;
float:left;
position:relative;
height:40px;
background:#CECECE;
text-align:center;
font-size:20px;
border:1 #F4F4F4 groove;
color:#FFF;
}
#ul1 li ul{
list-style-type:none;
display:none;
position:absolute;
top:40px;
margin-top:1px;
} <!--display:none隐藏导航栏的小导航(即aaaa)-->
#ul1 li ul li{
width:188px;
}
#ul1 li a:link{
display:block;
height:40px;
text-decoration:none;
color:#F7F7F7;
}<!--伪类-->
#ul1 li a:visited{
background:#585858;
}
#ul1 li a:hover{
background:#CCFFCC;
}
</style>
<script>
function display(li){
var dis=li.getElementsByTagName("ul")[0];
dis.style.display="block";
}
function hiddle(li){
var hid=li.getElementsByTagName("ul")[0];
hid.style.display="none";}
</script></head>
<body><div id="center">
<ul id="ul1">
<li onMouseOver="display(this)" onMouseOut="hiddle(this)">number1
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)"> number2
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)" >number3
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)" >number4
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
<li onMouseOver="display(this)" onMouseOut="hiddle(this)" >number5
<ul>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
<li><a href="#">aaaa</a></li>
</ul></li>
</ul>
</div>
</body>
</html>