javascript countdown timer with start & stop buttons

javascript counter countdown countdowntimer
Tommi Tiihonen picture Tommi Tiihonen · Nov 16, 2016 · Viewed 20k times · Source

I need to make a simple countdown timer from 5 to zero, with the buttons to START and STOP the counter. The only thing that I don't know is that why won't my counter stop.

The code is presented below:

Answer

Feathercrown picture Feathercrown · Nov 16, 2016

Here you go, you just needed to make myTimer global. I also fixed a glitch where after resetting the timer, it won't show 5.

var myTimer;
   function clock() {
     myTimer = setInterval(myClock, 1000);
     var c = 5;

     function myClock() {
       document.getElementById("demo").innerHTML = --c;
       if (c == 0) {
         clearInterval(myTimer);
         alert("Reached zero");
       }
     }
   }
<p id="demo">5</p>
<button onclick="clock(); document.getElementById('demo').innerHTML='5';">Start counter</button>
<button onclick="clearInterval(myTimer);">Stop counter</button>

Related questions

How to set one minute counter in javascript?

In my project ,I have list of questions, for every question have three option answers. After see the question if i want answer that question means click "show answer" button . when I click button ,counter starts for one minute after …

Read More
Get loop counter/index using for…of syntax in JavaScript

Caution: question still applies to for…of loops.> Don't use for…in to iterate over an Array, use it to iterate over the properties of an object. That said, this I understand that the basic for…in syntax in …

Read More
HTML/Javascript Button Click Counter

I have done something similar to this before, and I know this is really close. I'm just trying to make it so that my button increments the javascript variable, and the function then displays the new value. <html> &…

Read More