将yyyy-MM-dd hh:mm:ss转换为时间戳

			// 转为时间戳//2014-07-10 10:21:12的时间戳为：1404958872 
			zhuanhuan(stringTime){
				// var stringTime = "2014-07-10 10:21:12";
				var timestamp2 = stringTime.replace(/-/g, '/')   //为了兼容IOS，需先将字符串转换为'2018/9/11 9:11:23'
				timestamp2 = Date.parse(timestamp2)    //返回'2018-9-12 9:11:23'的时间戳
				console.log(stringTime + "的时间戳为：" + timestamp2);
				return timestamp2;
			},