//格式化时间
Date.prototype.format = function (format) {
    var o = {
        "M+": this.getMonth() + 1, //month
        "d+": this.getDate(), //day
        "h+": this.getHours(), //hour
        "m+": this.getMinutes(), //minute
        "s+": this.getSeconds(), //second
        "q+": Math.floor((this.getMonth() + 3) / 3), //quarter
        "S": this.getMilliseconds() //millisecond
    };
    if (/(y+)/.test(format)) format = format.replace(RegExp.$1,
        (this.getFullYear() + "").substr(4 - RegExp.$1.length));
    for (var k in o)
        if (new RegExp("(" + k + ")").test(format))
            format = format.replace(RegExp.$1,
                RegExp.$1.length == 1 ? o[k] :
                    ("00" + o[k]).substr(("" + o[k]).length));
    return format;
};

// 对toFixed数字保留位数二次封装（ps：toFixed返回的是字符串）
Number.prototype.toHold = function (value) {
    var hold = this.toFixed(value);
    hold = Number(hold);
    return hold;
};