The example below (just sample code) it will count 5 secs and then alert the total seconds. You need to make the math to get hours, minutes, seconds.

$(document).ready(function(){

var secs = 0;

var id = setInterval(function(){ 

    secs++; console.log(secs);

  if(secs> 5){

    clearInterval(id);

    alert('Total Time: ' + secs + ' seconds');

   }

}, 1000);

});

Then you can put the logic inside a start/stop method or wherever you need to place it.

With pure Javascript:

window.onload = function() {

var secs = 0;

    var id = setInterval(function(){ 

        secs++; console.log(secs);

      if(secs> 5){

        clearInterval(id);

        alert('Total Time: ' + secs + ' seconds');

       }

    }, 1000);

};