HTML JS给字符串和日期增加format函数

Date.prototype.format = function(format) {
	var o = {
		"M+" : this.getMonth() + 1,
		"d+" : this.getDate(),
		"h+" : this.getHours(),
		"m+" : this.getMinutes(),
		"s+" : this.getSeconds(),
		"q+" : Math.floor((this.getMonth() + 3) / 3),
		"S" : this.getMilliseconds()
	};
	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;
};

String.format = function(src){
	if (arguments.length === 0) return null;
	var args = Array.prototype.slice.call(arguments, 1);
	return src.replace(/\{(\d+)\}/g, function(m, i){
		return args[i];
	});
};