function setCookie(name,value,days){ 
var exp=new Date(); 
exp.setTime(exp.getTime() + days*24*60*60*1000); 
var arr=document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)")); 
document.cookie=name+"="+escape(value)+";expires="+exp.toGMTString(); 
} 
function getCookie(name){ 
var arr=document.cookie.match(new RegExp("(^| )"+name+"=([^;]*)(;|$)")); 
if(arr!=null){ 
return unescape(arr[2]); 
return null; 
} 
} 
function delCookie(name){ 
var exp=new Date(); 
exp.setTime(exp.getTime()-1); 
var cval=getCookie(name); 
if(cval!=null){ 
document.cookie=name+"="+cval+";expires="+exp.toGMTString(); 
} 
}