JS时间格式化函数

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;
        }