1-Min Countdown Javascript

Question

I'm attempting to build a typing test that begins counting down when the user presses a key in the text area. I thought an if-else loop would help display and start the 1-minute countdown timer in my HTML but that's not the case.

Please explain to me what I'm doing wrong & how to correct my code.

HTML:

<div id="timer"></div>
<p>Text for typing test will go here.</p>
<textarea id="textarea" rows="14" cols="150" placeholder="Start typing here...">
</textarea>`

JS:

var seconds=1000 * 60; //1000 = 1 second in JS
var min = seconds * 60;
var textarea = document.getElementById("textarea").onkeypress = function() { 
    myFunction()
};
//When a key is pressed in the text area, update the timer using myFunction

function myFunction() {
   document.getElementById("timer").innerHTML = 
     if (seconds>=0) {
         seconds = seconds--;
     } else {
         clearInterval("timer");
         alert("You type X WPM");
     }
} //If seconds are equal or greater than 0, countdown until 1 minute has passed
//Else, clear the timer and alert user of how many words they type per minute

document.getElementById("timer").innerHTML="0:" + seconds; 

Answer 1

There are some problems with your solution that I noticed.

1) You clearInterval, but you never setInterval

2) seconds = seconds--, does not do what you think it does because of order of operations in JavaScript.

I modified your JS and have a working solution in this codepen

JS:

var seconds=60;
var timer;
function myFunction() {
  if(seconds < 60) { // I want it to say 1:00, not 60
    document.getElementById("timer").innerHTML = seconds;
  }
  if (seconds >0 ) { // so it doesn't go to -1
     seconds--;
  } else {
     clearInterval(timer);
     alert("You type X WPM");
  }
}
document.getElementById("textarea").onkeypress = function() {
  if(!timer) {
    timer = window.setInterval(function() { 
      myFunction();
    }, 1000); // every second
  }
} 

document.getElementById("timer").innerHTML="1:00";