格式化时间

Date.prototype.formatDate = function (fmt) {
	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(fmt))
		fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
	for (var k in o)
		if(o.hasOwnProperty(k)){
			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;
};


// 用
let formattedTime = new Date().formatDate("hh:mm");

console.log(formattedTime);