javascript 对日期加减操作 格式化

/**
 * js 对date加减
 */



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;
}

Date.prototype.addDays = function(d) {
	this.setDate(this.getDate() + d);
};

Date.prototype.addWeeks = function(w) {
	this.addDays(w * 7);
};

Date.prototype.addMonths = function(m) {
	var d = this.getDate();
	this.setMonth(this.getMonth() + m);

	if (this.getDate() < d)
		this.setDate(0);
};

Date.prototype.addYears = function(y) {
	var m = this.getMonth();
	this.setFullYear(this.getFullYear() + y);

	if (m < this.getMonth()) {
		this.setDate(0);
	}
};

//js格式化时间
Date.prototype.toDateString = function(formatStr) {
	var date = this;
	var timeValues = function() {
	};
	timeValues.prototype = {
		year : function() {
			if (formatStr.indexOf("yyyy") >= 0) {
				return date.getYear();
			} else {
				return date.getYear().toString().substr(2);
			}
		},
		elseTime : function(val, formatVal) {
			return formatVal >= 0 ? (val < 10 ? "0" + val : val) : (val);
		},
		month : function() {
			return this.elseTime(date.getMonth() + 1, formatStr.indexOf("MM"));
		},
		day : function() {
			return this.elseTime(date.getDate(), formatStr.indexOf("dd"));
		},
		hour : function() {
			return this.elseTime(date.getHours(), formatStr.indexOf("hh"));
		},
		minute : function() {
			return this.elseTime(date.getMinutes(), formatStr.indexOf("mm"));
		},
		second : function() {
			return this.elseTime(date.getSeconds(), formatStr.indexOf("ss"));
		}
	}
	var tV = new timeValues();
	var replaceStr = {
		year : ["yyyy", "yy"],
		month : ["MM", "M"],
		day : ["dd", "d"],
		hour : ["hh", "h"],
		minute : ["mm", "m"],
		second : ["ss", "s"]
	};
	for (var key in replaceStr) {
		formatStr = formatStr.replace(replaceStr[key][0], eval("tV." + key
				+ "()"));
		formatStr = formatStr.replace(replaceStr[key][1], eval("tV." + key
				+ "()"));
	}
	return formatStr;
}

function formatStrDate(date) {
	var str = date.toDateString("yyyy-MM-dd hh:mm:ss");
	if (str.indexOf("00:00:00") != -1) {
		return str.replace("00:00:00", "10:00:00");
	}
	return str;
}

var date = new Date();
date.addDays(-3);
console.info(date.toDateString("yyyy-MM-dd hh:mm:ss"));