title: Countdown won't stop at 0, keeps decrementing
body: <p>I have a timer that keeps decrementing after 0 so I get negative numbers. Time starts when a button is clicked and the pauses when the same button is clicked again.</p>
  <pre><code>button.addEventListener(&quot;click&quot;, function(event){
      console.log('timer started')
      // Timer paused, click to start
  
              // Pause/Play Timer
              if(timeleft == 90){
                  timeleft = setInterval(function() {
                      time--;
                      timerDisplay.innerHTML = time;
                  }, 1000);
              } else if (timeleft === 0) {
                  clearInterval(timeleft);
              } else{   
              // Timer running, click to pause
                console.log('timer paused')
                  clearInterval(timeleft);
                  timeleft = 90;
              }
          });
  </code></pre>
  <p>The stop and start functionality works fine but why won't it stop counting down once it reaches 0?</p>