documentmozFullScreenElement

The documentmozFullScreenElement property is a read-only property of the Document interface in web development. It returns the Element that is currently being presented in full-screen mode, or null if full-screen mode is not currently active. This property is part of the Fullscreen API, which allows web applications to control the display of elements in full-screen mode.

The Fullscreen API provides several methods and events to manage full-screen mode, including requestFullscreen() to enter full-screen mode, exitFullscreen() to exit full-screen mode, and fullscreenchange and fullscreenerror events to handle changes in full-screen state and errors, respectively.

The documentmozFullScreenElement property is specific to the Mozilla Firefox browser, which uses the "moz" prefix for its proprietary or experimental features. In other browsers, the equivalent property is document.fullscreenElement. It is important to note that the Fullscreen API is still in the process of being standardized, and browser support may vary.

Developers should use feature detection to check for the availability of the Fullscreen API and its properties before attempting to use them. This ensures compatibility across different browsers and versions. Additionally, it is recommended to handle full-screen mode changes gracefully, providing fallback mechanisms for browsers that do not support the Fullscreen API.