js倒计时120分钟

var userTime = 120;
var userTimes = 120 * 60 * 1000;
console.log('用户限定毫秒数' +userTimes);
var data = new Date();
var now = data.getTime();
console.log('现在的时间' + now);
var endTime = now + userTimes;
console.log('结束的时间' + endTime);
			
var timer = setInterval(function(){
	leftTime();
},100)
			
function leftTime() {
	var data = new Date();
	var nowTime = data.getTime();
	var chaTime = endTime - nowTime;
	//倒计时的时间
	if (chaTime >= 0) {
		var d = Math.floor(chaTime / 1000 / 60 / 60 / 24);
		var h = Math.floor(chaTime / 1000 / 60 / 60 % 24);
		var m = Math.floor(chaTime / 1000 / 60 % 60);
		var s = Math.floor(chaTime / 1000 %60);
	}
	$('.time').html(d + '天' + h + '时' + m + '分' + s + '秒');
}