一个tab标签切换效果代码

<div class="tab">
<div id="tabsK">
<ul id="menu4">
<li onclick="settab(4,0)" class="hover"><a title="最新更新"><span>最新更新</span></a></li>
<li onclick="settab(4,1)"><a title="企业新闻"><span>企业新闻</span></a></li>
<li onclick="settab(4,2)"><a title="行业新闻"><span>行业新闻</span></a></li>
<li onclick="settab(4,3)"><a title="专栏文章"><span>专栏文章</span></a></li>
<li onclick="settab(4,4)"><a title="科技新闻"><span>科技新闻</span></a></li>
</ul>
</div>

<div class="tab2" id="main4">
<ul class="block"></ul>
<ul ></ul>
<ul ></ul>
<ul ></ul>
<ul ></ul>
</div>
</div>

#tabsK {
float:left;
width:100%;
line-height:normal;
border-bottom:1px solid #54545C;
}
#tabsK ul {
margin:0;
padding:10px 10px 0 10px;
list-style:none;
}
#tabsK li {
display:inline;
margin:0;
padding:0;
cursor:pointer;
}
#tabsK a {
float:left;
background:url("?article/image/tableftK.gif") no-repeat left top;
margin:0;
padding:0 0 0 4px;
text-decoration:none;
}
#tabsK a span {
float:left;
display:block;
background:url("?article/image/tabrightK.gif") no-repeat right top;
padding:8px 16px 4px 6px;
color:#FFF;
}

#tabsK a span {float:none;}
/* End IE5-Mac hack */
#tabsK a:hover span {
cursor:pointer;
color:#FFF;
background-position:100% -42px;
}
#tabsK a:hover {
background-position:0% -42px;
cursor:pointer;
}
#tabsK .hover a
{
background-position:0% -42px;
}
#tabsK .hover span
{
background-position:100% -42px;
}

.tab2 ul
{
display:none;
list-style-type:none;
height:560px;
}
.tab2 ul li
{
text-align:left;
line-height:20px;
text-indent:1em;
}
.tab2 .block
{
display:block;
}

<script language="javascript"><!--
function settab(m,n){
var tli=document.getElementById("menu"+m).getElementsByTagName("li");
var mli=document.getElementById("main"+m).getElementsByTagName("ul");
for(i=0;i<tli.length;i++){
tli[i].className=i==n?"hover":"";
mli[i].style.display=i==n?"block":"none";
}
}
// --></script>