javascript cookie

  //设置cookie
        function setCookie(name, value, day) { 
            var date=new Date();
            date.setDate(date.getDate() + day);
            document.cookie = name + "=" + escape(value) + ((day == null) ? "" : ";expires=" + date.toGMTString());
        }
        setCookie("username", "perter", 3);
        setCookie("password", "123", 3);
        //获取cookie
        function getCookie(name){
            var arr1 = document.cookie.split("; ");
            var j =0;
            for (j; j<arr1.length; j++) {
                var arr2 = arr1[j].split("=");
                if (arr2[0] == name)
                {
                    return arr2[1];
                }
            }
            return "";
        }
        alert(getCookie("username")); //perter

        //删除cookie
        function removeCookie(name) {
            setCookie(name, "", -1);
        }
        removeCookie("username");
        alert(getCookie("username")); //返回空字符串