js操作cookie

    //写入cookie
    function setCookie(name, value) {
        var Days = 30;
        var exp = new Date();
        exp.setTime(exp.getTime() + Days * 24 * 60 * 60 * 1000);
        document.cookie = name + "=" + escape(value) + ";expires=" + exp.toGMTString();
    }
    //读取cookies 
    function getCookie(name) {
        var arr, reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");

        if (arr = document.cookie.match(reg))

            return unescape(arr[2]);
        else
            return null;
    }
    //删除cookies 
    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();
    }