//写cookies函数
function SetCookie(name,value)//两个参数,一个是cookie的名子,一个是值
{
        var Days = 30; //此 cookie 将被保存 30 天
        var exp    = new Date();        //new Date("December 31, 9998");
        exp.setTime(exp.getTime() + Days*24*60*60*1000);
        document.cookie = name + "="+ escape (value) + ";expires=" + exp.toGMTString();
}
 

function delCookie(name)//删除cookie
{
        var exp = new Date();
        exp.setTime(exp.getTime() - 1);
        var cval=getCookie(name);
        if(cval!=null) document.cookie= name + "="+cval+";expires="+exp.toGMTString();
}
 
 

function getCookie(Name)    
{    
        var search = Name + "="    
        if(document.cookie.length > 0)    
        {    
                offset = document.cookie.indexOf(search)    
                if(offset != -1)    
                {    
                        offset += search.length    
                        end = document.cookie.indexOf(";", offset)    
                        if(end == -1) end = document.cookie.length    
                        return unescape(document.cookie.substring(offset, end))    
                }    
                else return ""    
        }    
}