Using the Fullscreen API

In this article, we’ll cover the Fullscreen API with ample amounts of code snippets, and interactive demos. It’s a suprisingly easy API to work with!

The Fullscreen API was introduced in 2013, and provides a native way for browsers to enter/exit fullscreen mode. This specification brought a slew of JavaScript APIs, and CSS selectors that we can use to refine this immersive user experience.

Basics of the Fullscreen API

It’s really easy to activate fullscreen mode on the web! Currently, some browsers still require prefixing the requestFullscreen method.

To check which Fullscreen API method is available, you can create a helper function similar to this:

function activateFullscreen(element) {
  if(element.requestFullscreen) {
    element.requestFullscreen();        // W3C spec
  }
  else if (element.mozRequestFullScreen) {
    element.mozRequestFullScreen();     // Firefox
  }
  else if (element.webkitRequestFullscreen) {
    element.webkitRequestFullscreen();  // Safari
  }
  else if(element.msRequestFullscreen) {
    element.msRequestFullscreen();      // IE/Edge
  }
};

The word "request" in requestFullscreen is due to the fact that browsers don't have permissions (by default) to activate fullscreen mode.

Exiting fullscreen is pretty easy, but it also requires a bit of browser detection:

function deactivateFullscreen() {
  if(document.exitFullscreen) {
    document.exitFullscreen();
  } else if (document.mozCancelFullScreen) {
    document.mozCancelFullScreen();
  } else if (document.webkitExitFullscreen) {
    document.webkitExitFullscreen();
  }
};

Using the above function, to activate fullscreen, simply pass the document HTMLElement!

<button
  onclick="activateFullscreen(document.documentElement);"
>
  Go fullscreen!
</button>

<button
  onclick="deactivateFullscreen();"
>
  Leave fullscreen
</button>

See the Pen alligatorio-fullscreen-api-1 by wle8300 ( @wle8300 ) on CodePen .

Using Fullscreen API on unconventional HTMLElements

As you might have guessed, other HTML hlements can go into fullscreen mode too, not just document !

In the demo below, try clicking the buttons to make <h1> , <img> , and <video> go into fullscreen mode:

<button
  onclick="activateFullscreen(document.getElementById('my-image'));"
>
  Fullscreen #my-text!
</button>
<button
  onclick="activateFullscreen(document.getElementById('my-image'))"
>
  Fullscreen #my-image
</button>
<button
  onclick="activateFullscreen(document.getElementById('my-video'))"
>
  Fullscreen #my-video
</button>

<h1 id="my-text">Hello world</h1>
<img id="my-image" src="alligatorio-logo.svg" width="200"/>
<video id="my-video" controls src="big-buck-bunny.mp4" />

See the Pen alligatorio-fullscreen-api-2 by wle8300 ( @wle8300 ) on CodePen .

Properties & Events

There are additional properties that Fullscreen API brings:

• document.fullScreenEnabled : returns a boolean denoting whether the webpage has permissions to enter fullscreen mode
• document.fullScreenElement : returns a HTMLElement Node (only when fullscreen is activated)

You’ll also need to detect the browser:

const fullscreenEnabled = document.fullscreenEnabled
  || document.mozFullScreenEnable
  || document.webkitFullscreenEnabled;
const fullscreenElement = document.fullscreenElement
  || document.mozFullScreenElemen
  || document.webkitFullscreenElement;

There’s also an event called fullscreenchange when the user enters/exits fullscreen mode that you can listen to:

const fullscreenElement = document.fullscreenElement
  || document.mozFullScreenElement
  || document.webkitFullscreenElement;

document.addEventListener('fullscreenchange', (event) => {
  if (fullscreenElement) {
    console.log('Entered fullscreen:', document.fullscreenElement);
  } else {
    console.log('Exited fullscreen.');
  }
});

Styling Fullscreen Elements

On top of the JavaScript API that’s available, there’s also a few CSS pseudo-classes you can use:

/* Targets the
  HTML element that's
  in fullscreen mode */
:fullscreen,
:-webkit-full-screen,
:-moz-full-screen,
:-ms-fullscreen {
  /* ... */
}


/* Styling the
  backdrop */
::backdrop {
  /* ... */
}

Here’s an example where we add a groovy background-color , and opacity rules to the backdrop:

::backdrop {
  opacity: 0.8;
  background: #DFA612;
}

See the Pen alligatorio-fullscreen-api-3 by wle8300 ( @wle8300 ) on CodePen .

Try clicking the button! You can read more about :fullscreen and :backdrop on the Mozilla Developer Network.

The W3C specification alternated between "fullscreen" and "full-screen" so you'll see a discrepancy in older specs, browser prefixes, etc. Going forward browsers will stick with "fullscreen"