<div id="wrap">
 <a href="#">web标准学习</a>
 <a href="#">css</a>
 <a href="#">javascript</a>
 <a href="#">html5</a>
 <a href="#">canvas</a>
 <a href="#">video</a>
 <a href="#">audio</a>
 <a href="#">jQuery</a>
 <a href="#">jQuerymobile</a>
 <a href="#">flash</a>
 <a href="#">firefox</a>
 <a href="#">chrome</a>
 <a href="#">opera</a>
 <a href="#">IE9</a>
 <a href="#">css3.0</a>
 <a href="#">andriod</a>
 <a href="#">apple</a>
 <a href="#">google</a>
 <a href="#">jobs</a>
 </div>

window.onload=function(){
 var obox=document.getElementById("wrap");
 var obj=obox.getElementsByTagName("a");
 //随机方法
 function rand(num){
  return parseInt(Math.random()*num+1);
 }
 //随机颜色值
 function randomcolor(){
  var str=Math.ceil(Math.random()*16777215).toString(16);
  if(str.length<6){
   str="0"+str;
  }
  return str;
 }
 //循环
 for( len=obj.length,i=len;i--;){
  obj[i].className="color"+rand(5);
  obj[i].style.zIndex=rand(5);
  obj[i].style.fontSize=rand(12)+12+"px";
  // obj[i].style.background="#"+randomcolor();
  obj[i].style.color="#"+randomcolor();
  obj[i].onmouseover=function(){
   this.style.background="#"+randomcolor();
  }
  obj[i].onmouseout=function(){
   this.style.background="none";
  }
 }
}