Science Knowings: HTML Course For Social Media

HTML5 Page Visibility API

HTML5 Page Visibility API

Dive into HTML5's Page Visibility API!

In our previous session, we explored Server-Sent Events. Now, let's uncover the Page Visibility API, a powerful tool for managing webpage visibility.

What is the Page Visibility API?

The Page Visibility API provides a way to monitor the visibility of a webpage, meaning when it's active in the user's browser tab.

Benefits and Use Cases

  • Optimize user experience: Pause media, stop animations, or save battery life when the page isn't visible.
  • Enhance performance: Reduce resource consumption when the page is inactive.

Browser Support

BrowserSupport
ChromeYes
FirefoxYes
SafariYes
EdgeYes
Internet ExplorerNo

How to Use the Page Visibility API

Access the API through the document.visibilityState property and use addEventListener() to listen for visibility changes.

Properties: document.hidden

The document.hidden property indicates whether the page is currently hidden or not. It's set to true when the page is not visible and false otherwise.

undefined

The addEventListener() method is used to listen for visibility changes on the webpage. It takes two arguments: the event type and a callback function.

addEventListener() - Event Listeners

document.addEventListener('visibilitychange', () => {
 // Code to execute when visibility changes
});

Syntax for addEventListener()

addEventListener(type, listener, options);
  • type: The event to listen for ('visibilitychange' in our case)
  • listener: The callback function to execute
  • options: Optional options object

Page Visibility Events

  • visibilitychange: Triggered when the visibility of the page changes.

Page Visibility API Example

document.addEventListener('visibilitychange', () => {
 console.log(document.hidden ? 'Page is hidden' : 'Page is visible');
});

Page Visibility API Polyfill

For browsers that don't natively support the Page Visibility API, a polyfill can be used:

if (!document.hidden) {
Object.defineProperty(document, 'hidden', {
get: () => document.visibilityState === 'hidden'
});
}

Applications of the Page Visibility API

  • Battery optimization
  • Media playback control
  • Animation pausing
  • Data fetching throttling

Best Practices for Using the Page Visibility API

  • Combine visibility events with other performance optimization techniques.
  • Use the API responsibly, respecting user preferences.

Next Topic: HTML5 Video API

Explore Video Playback like never before!

In the next session, we'll delve into the HTML5 Video API, empowering you to add interactive video experiences to your web pages. Follow us to stay tuned!