效果展示：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
    </head>
    <body>
    </body>
    <script>
        window.onload = function() {
            var interVal = setInterval(function(){
                var endTime = 1558598070;
                if(endTime <= Date.parse(new Date())/1000){
                    clearInterval(interVal);
                }else{
                    var timeStr = timeInterval(endTime);
                    console.log(timeStr);
                }
            },1000);
            
            // timeInterval2(1558596900)
        }
        
        var timeInterval = function(endTime){
            var nowTime = Date.parse(new Date()); // 获取现在的时间的时间戳
            var time = endTime - nowTime/1000; //时间差：
            var day = 0,
                hour = 0,
                minute = 0,
                second = 0,
                result = '';
            if (time >= 0) {
                day = Math.floor(time / (60 * 60 * 24)); //相差天數
                hour = Math.floor(time / (60 * 60))-day * 24; //相差小时
                minute = Math.floor(time % 3600 /  60); //相差分钟
                second = Math.floor(time % 3600 % 60);
                if (day<=9) {day = "0" + day;}
                if (hour<=9) {hour = "0" + hour;}
                if (minute<=9) {minute = "0" + minute;}
                if (second<=9) {second = "0" + second;}
                result = day + "天" + hour + ":" + minute + ":" + second;
                return result;
            }
        }
        
        var timeInterval2 = function(endTime){
            var intervalName = setInterval(function(){
                var nowTime = Date.parse(new Date()); // 获取现在的时间的时间戳
                var time = endTime - nowTime/1000; //时间差：
                var day = 0,
                    hour = 0,
                    minute = 0,
                    second = 0,
                    result = '';
                if (time >= 0) {
                    day = Math.floor(time / (60 * 60 * 24)); //相差天數
                    hour = Math.floor(time / (60 * 60))-day * 24; //相差小时
                    minute = Math.floor(time % 3600 /  60); //相差分钟
                    second = Math.floor(time % 3600 % 60);
                    if (day<=9) {day = "0" + day;}
                    if (hour<=9) {hour = "0" + hour;}
                    if (minute<=9) {minute = "0" + minute;}
                    if (second<=9) {second = "0" + second;}
                    result = day + "天" + hour + ":" + minute + ":" + second;
                    console.log(result);
                }
                if(day==0 && hour==0 && minute==0 && second==0){
                    clearInterval(intervalName);
                }
            },1000);
        }
        
    </script>
</html>