function setCookie(name,value) {     
        var never = new Date();   
        //设置Cookie的有效期   
        never.setTime(never.getTime() + 3600*1000*24); 
        var expString = "expires=" + never.toGMTString() +";";   
        document.cookie = name+"=" + escape(value) +"; " + expString;
	   
 }      
function getCookie(name) {     
    var result = null;   
    var myCookie = " " + document.cookie + ";";   
    var searchName = " " + name + "=";   
    var startOfCookie = myCookie.indexOf(searchName);   
    var endOfCookie;   
    if (startOfCookie != -1)    
    {   
  
        startOfCookie += searchName.length;    
        endOfCookie = myCookie.indexOf(";", startOfCookie);   
        result = unescape(myCookie.substring(startOfCookie, endOfCookie));   
    }   
    return result;   
       
  }   
function delCookie(name){//为了删除指定名称的cookie，可以将其过期时间设定为一个过去的时间   
       var date = new Date();   
       date.setTime(date.getTime() - 10000);   
       document.cookie = name + "=a; expires=" + date.toGMTString();   
}