javascript - Add "0" to countdown timer after it reaches 0 -

so basicly have countdown timer add "0" once reaches below "10". far have tried if statement (in code below) did not work. here full code:

countdowntimer('01/1/2017 12:0 am', 'countdown');   countdowntimer('01/1/2017 12:0 am', 'newcountdown');    function countdowntimer(dt, id)   {       var end = new date(dt);       var _second = 1000;       var _minute = _second * 60;       var _hour = _minute * 60;       var _day = _hour * 24;       var timer;        function showremaining() {           var = new date();           var distance = end - now;           if (distance < 0) {               clearinterval(timer);               document.getelementbyid(id).innerhtml = 'expired!';               return;           }           var days = math.floor(distance / _day);           var hours = math.floor((distance % _day) / _hour);           var minutes = math.floor((distance % _hour) / _minute);           var seconds = math.floor((distance % _minute) / _second);            // "if" statement did not work, else working           if (seconds < 10) {             document.getelementbyid(id).innerhtml += '0' + seconds + '.';           }            document.getelementbyid(id).innerhtml = days + '.&nbsp;&nbsp;&nbsp;';           document.getelementbyid(id).innerhtml += hours + '.&nbsp;&nbsp;&nbsp;';           document.getelementbyid(id).innerhtml += minutes + '.&nbsp;&nbsp;&nbsp;';           document.getelementbyid(id).innerhtml += seconds + '.';       }        timer = setinterval(showremaining, 1000);   } 

the problem code not if, working:

if (seconds < 10) {     document.getelementbyid(id).innerhtml += '0' + seconds + '.'; } 

but fact that, after that, overwriting previous value:

document.getelementbyid(id).innerhtml += seconds + '.'; 

an easy solution converting seconds string, in if:

if (seconds < 10) {     seconds = "0" + seconds; } 

this way, can use string in subsequent innerhtml.