var Cookie = { 
    // 读取
    read : function(name){ 
        var cookieStr = "; "+document.cookie+"; "; 
        var index = cookieStr.indexOf("; "+name+"="); 
        if (index!=-1){ 
            var s = cookieStr.substring(index+name.length+3,cookieStr.length); 
            return unescape(s.substring(0, s.indexOf("; "))); 
        }else{ 
            return null; 
        } 
    }, 
    // 设置
    set : function(name,value,expires){ 
        var expDays = expires*24*60*60*1000; 
        var expDate = new Date(); 
        expDate.setTime(expDate.getTime()+expDays); 
        var expString = expires ? "; 
        expires="+expDate.toGMTString() : ""; 
        var pathString = ";path=/"; 
        document.cookie = name + "=" + escape(value) + expString + pathString; 
    }, 
    // 删除
    del : function(name){ 
        var exp = new Date(new Date().getTime()-1); 
        var s=this.read(name); 
        if(s!=null) {
            document.cookie= name + "="+s+";
            expires="+exp.toGMTString()+";path=/"
        }
    } 
};
// demo:
Cookie.set("mayb", "www.mayb.cn", 7);
alert(Cookie.read("mayb"));
Cookie.del("mayb");