Page Visibility shim for jQuery

This plugin gives you a very simple API that allows you to execute callbacks when the page’s visibility state changes.

It does so by using the Page Visibility API where it’s supported, and falling back to good old focus and blur in older browsers.

Demo

http://mathiasbynens.be/demo/jquery-visibility

When to use?

Typical use cases include but are not limited to pausing/resuming slideshows, video, and/or embedded audio clips.

Example usage

This plugin simply provides two custom document events for you to use: show and hide. When the page visibility state changes, the appropriate event will be triggered.

You can use them separately:

$(document).on('show', function() {
  // the page gained visibility
});

$(document).on('hide', function() {
  // the page was hidden
});

For most applications you'll need both events, so the most convenient option is to use an events map. This way, you can bind both event handlers in one go:

$(document).on({
  'show': function() {
    console.log('The page gained visibility; the `show` event was triggered.');
  },
  'hide': function() {
    console.log('The page lost visibility; the `hide` event was triggered.');
  }
});

Or bind both to the same callback and distinguish using the event variable.

$(document).on('show hide', function (e) {
	console.log('The page is now', e.type === 'show' ? 'visible' : 'hidden');
});

The plugin will detect if the Page Visibility API is natively supported in the browser or not, and expose this information as a boolean (true/false) in $.support.pageVisibility.
Warning: $.support was marked deprecated in jQuery version 1.9, so it is likely to be removed in the future.

if ($.support.pageVisibility) {
  // Page Visibility is natively supported in this browser
}

If the Page Visibility API is supported the plugin will also store the current visibility state in document.hidden.

if (!document.hidden) {
  // Page is currently visible
}

Notes

This plugin is not a Page Visibility polyfill, as it doesn’t aim to mimic the standard API. It merely provides a simple way to use this functionality (or a fallback) in your jQuery code.

License

This plugin is available under the MIT license.

Author

Mathias Bynens

Contributors

Jan Paepke, John-David Dalton