js倒计时如火车站买火车票后15分钟必须付款否则取消火车票

js倒计时如火车站买火车票后15分钟必须付款否则取消火车票

$(function(){

timer();
});

function timer(){

interval = setInterval("timer1()",1000);
}

function timer1(){
var leftTime =  new Date().getTime() -  dateTime.getTime();
leftTime = 15*60*1000  - leftTime;
var minute =parseInt(leftTime/1000/60%60,10);
var second = parseInt(leftTime/1000%60,10);
var min = checkTime(minute);
var sec = checkTime(second);
$("#leftTimeTag").html(min + ":" + sec);
if(leftTime < 1000){
alert("hello 倒计时结束");
clearInterval(interval);
}
}

function checkTime(i){
if(i < 10 ){
i = "0" + i;
}
return i;
}