js时间操作扩展方法

//时间操作
Date.prototype.addYears = function (y) {
var m = this.getMonth();
this.setFullYear(this.getFullYear() + y);
if (m < this.getMonth()) {
this.setDate(0);
}
};

Date.prototype.addMonths = function (m) {
var d = this.getDate();
this.setMonth(this.getMonth() + m);
if (this.getDate() < d) this.setDate(0);
};

Date.prototype.addWeeks = function (w) {
this.addDays(w * 7);
};
Date.prototype.addDays = function (d) {
this.setDate(this.getDate() + d);
};
Date.prototype.Format = function (fmt) {
//author: meizz
var o = { "M+": this.getMonth() + 1,
//月份
"d+": this.getDate(),
//日
"h+": this.getHours(),
//小时
"m+": this.getMinutes(),
//分
"s+": this.getSeconds(),
//秒
"q+": Math.floor((this.getMonth() + 3) / 3),
//季度
"S": this.getMilliseconds()
//毫秒
};
if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
for (var k in o) if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length))); return fmt;
}