title: JavaScript start counting from timestamp
body: <p>I have this counter that I want to start from a specific timestamp (1385132831.818785) instead of 0. How do I do that?</p>
  
  <pre><code>startTimer: function(el) {      
  
           var counter = 0, 
           cDisplay = $(el);
           var format = function(t) {
  
               var minutes = Math.floor(t/600),
                   seconds = Math.floor( (t/10) % 60);
               minutes = (minutes === 0) ? "" : (minutes === 1)? minutes.toString()     + ' min ' : minutes.toString() + ' mins ';
               seconds = (seconds === 0) ? "" : seconds.toString() + ' secs';
               cDisplay.html(minutes + seconds);
           };
          setInterval(function() {
             counter++;
             format(counter);
          },100);
  
      }
  </code></pre>