function setOnloadEvent(func){
 var oldonload = window.onload;
 if(typeof window.onload != "function"){
  window.onload = func;
 }
 else{
    window.onload = function(){
     oldonload();
     func();
    }
 }
}
// --- 设置cookie
function setCookie(name,value,days) {
  if (days) {
    var date = new Date();
    date.setTime(date.getTime()+(days*24*60*60*1000));
    var expires = "; expires="+date.toGMTString();
  }
  else expires = "";
  document.cookie = name+"="+value+expires+"; path=/";
}
//--- 获取cookie
function getCookie(name) {
  var nameEQ = name + "=";
  var ca = document.cookie.split(';');
  for(var i=0;i < ca.length;i++) {
    var c = ca[i];
    while (c.charAt(0)==' ') c = c.substring(1,c.length);
    if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
  }
  return null;
}
function skin(){
 if(!document.getElementsByTagName) return false;
 if(!document.getElementById("skin")) return false;
 var skin_id="a";
 if(getCookie("id")!=null){
      skin_id=getCookie("id");
   }
 var span_id=skin_id+"_sp";
 var span_on=document.getElementById(span_id);
 document.body.className=skin_id;
 span_on.className="on";
 var skinType=document.getElementById("skin");
 var skin_nub=skinType.getElementsByTagName("em");
 for(var i=0; i<skin_nub.length;i++){
    skin_nub[i].onclick=function(){
    var em_id=this.getAttribute("id");
    var skin_id=em_id.split("_")[1];
    var spanList=document.getElementsByTagName("span");
    for(var j=0;j<spanList.length;j++){
       spanList[j].className="";
       if(spanList[j].getAttribute("id").indexOf(skin_id)!=-1)
       {
       spanList[j].className="on";
       }
    }
     document.body.className=skin_id;
    setCookie("id",skin_id,1);
   }
  }
}
setOnloadEvent(skin);