Js倒计时函数

//倒计时function timer(intDiff) {    var nextime = intDiff;    var intervalId = window.setInterval(function () {        nextime--;        var day = 0,        hour = 0,        minute = 0,        second = 0; //时间默认值        if (nextime > 0) {            day = Math.floor(nextime / (60 * 60 * 24)); //天            hour = Math.floor(nextime / (60 * 60)) - (day * 24); //小时            minute = Math.floor(nextime / 60) - (day * 24 * 60) - (hour * 60); //分钟            second = Math.floor(nextime) - (day * 24 * 60 * 60) - (hour * 60 * 60) - (minute * 60); //秒        }        if (hour <= 9)            hour = '0' + hour;        if (minute <= 9)            minute = '0' + minute;        if (second <= 9)            second = '0' + second;        $("#timeShow").html(minute + ":" + second);        if (nextime == 0) {            clearInterval(intervalId);        }    }, 1000);}