function menuFix() {
 var sfEls = document.getElementById("nav").getElementsByTagName("li");
 for (var i=0; i<sfEls.length; i++) {
  sfEls[i].onmouseover=function() {
  this.className+=(this.className.length>0? " ": "") + "sfhover";
  }
  sfEls[i].onMouseDown=function() {
  this.className+=(this.className.length>0? " ": "") + "sfhover";
  }
  sfEls[i].onMouseUp=function() {
  this.className+=(this.className.length>0? " ": "") + "sfhover";
  }
  sfEls[i].onmouseout=function() {
  this.className=this.className.replace(new RegExp("( ?|^)sfhover\\b"), "");
  }
 }
}
window.onload=menuFix;




function g(o){return document.getElementById(o);} 
function HoverLi(n){ 
//如果有N个标签,就将i<=N; 
//本功能非常OK,兼容IE7,FF,IE6; 
for(var i=1;i<=4;i++){g('tb_'+i).className='normaltab';g('tbc_0'+i).className='undis';}g('tbc_0'+n).className='dis';g('tb_'+n).className='hovertab'; 
} 
//如果要做成点击后再转到请将<li>中的onmouseover 改成 onclick;