//tab切换
function setTab(m,n){
 var tli=document.getElementById("tab"+m).getElementsByTagName("li");
 var mli=document.getElementById("main"+m).getElementsByTagName("ul");
 for(i=0;i<tli.length;i++){
  tli[i].className=i==n?"active":"";
  mli[i].style.display=i==n?"block":"none";
 }
}
function inputAutoClear(ipt){
  ipt.onfocus=function(){
    if(this.value==this.defaultValue){this.value='';}
  };
  ipt.onblur=function(){
    if(this.value==''){this.value=this.defaultValue;}
  };
  if(ipt.value==ipt.defaultValue){ipt.value='';}
}