cant auto submit after countdown

Question

please help, theres 2 things i want to asking about:

1. with that script, the count down just show an number, iwant the countdown shown as time format --:--:--

2. i cant auto submit after the countdown finish, and the count down wont stop after zero.

   <script>
   function timeOut(){
   alert("timeout");
   document.getElementById('myFormId').submit();
   }       
   (function () {
   var timeLeft = <?php echo ($data_test['TIME'] * 60) - $tb ?>,
       cinterval;
   
   var timeDec = function (){
       timeLeft--;
       document.getElementById('timer').innerHTML = timeLeft;
       if(timeLeft === 0){
           timeOut();
           clearInterval(cinterval);
       }
   };
   
   cinterval = setInterval(timeDec, 1000);
   })();
   </script>
   

Answer 1

var interval = 11; // Whatever.
function myTimer(interval){
  document.getElementById('timer').innerHTML = --interval;
  if (interval > 0) setTimeout(function(){myTimer(interval);}, 1000);
  else document.forms['myFormId'].submit();
}
myTimer(interval);

Something along these lines. Could be a lot better, but it's really just to give you an example right here. Shouldn't be much of a hazle.

Edit: Also see JavaScript seconds to time string with format hh:mm:ss for the formatting.