title: Countdown Timer only counts down 1 second then stops
body: <p>My countdown timer only counts down one second and then stops. I'm making a game that has a countdown clock and for ever incorrect answer, more time is added. I just can't get the timer to work.</p>
  <pre><code>var secondsLeft = document.getElementById(&quot;timer&quot;).textContent;
  
  var timer = setInterval(function() {
      secondsLeft = 120;
      secondsLeft--;
      document.getElementById(&quot;timer&quot;).textContent = secondsLeft;
  }, 1000);
  </code></pre>
  <p>I think I may need to do create a for loop, but everything I've read says I can do this without one.
  thanks!</p>