I am creating a game that when the play button is clicked, the timer starts. When my time is 0 I want to the paragraph with #timeline to be replaced with different text, which works perfectly. However how can I simultaneously add a .class to the replacement text so I can style "Your time is up!" differently when it is displayed.
    var secondsLeft = 20;
    function startTimer(){
      setInterval(myTimer, 1000);
    }
    function myTimer(){
      if(secondsLeft!=0){
        document.getElementById("time").innerHTML = secondsLeft-=1;
      } else {
        document.getElementById("timeLine").innerHTML = "Your time is up!"; 
      }
    }
 
     
    