Create a seconds countdown in 6 lines of JavaScript

TIL how to create a seconds countdown in just 6 lines of JavaScript.

The HTML:

<!-- Replace 10 with the seconds you want to count down from -->
<span id="countdown">10</span>

The JavaScript:

var seconds = document.getElementById("countdown").textContent;
var countdown = setInterval(function() {
    seconds--;
    document.getElementById("countdown").textContent = seconds;
    if (seconds <= 0) clearInterval(countdown);
}, 1000);

See above code in action on JSFiddle.

Running into a small challenge

I wanted to display xx seconds, but then I realised I must use second if 1 and seconds otherwise. I solved it this way:

The HTML:

<!-- Replace 10 with the seconds you want to count down from -->
<span id="countdown">10</span> second<span id="plural">s</span>

The JavaScript:

var seconds = document.getElementById("countdown").textContent;
var countdown = setInterval(function(){
    seconds--;
    (seconds == 1) ? document.getElementById("plural").textContent = "" : document.getElementById("plural").textContent = "s";
    document.getElementById("countdown").textContent = seconds;
    if (seconds <= 0) clearInterval(countdown);
},1000);

See above code in action on JSFiddle.

Where do I use this?

I use this at tonnygaric.com/github and tonnygaric.com/linkedin. On these pages I redirect users to, respectively, my GitHub and LinkedIn profile. I want to explicitly show users that they will be redirected in xx seconds.

I would love to shorten this code. If you know how, please share! 🙂

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UPDATE 2017-11-21: Joris Zwart shared a seconds countdown in 5 lines of JavaScript in the comments, see JSFiddle.

The HTML:

<span id="countdown"></span>

The JavaScript:

var seconds = 10, $seconds = document.querySelector('#countdown');
(function countdown() {
    $seconds.textContent = seconds + ' second' + (seconds == 1 ?  '' :  's')
    if(seconds --> 0) setTimeout(countdown, 1000)
})();