Window: fullScreen property
Non-standard: This feature is not standardized. We do not recommend using non-standard features in production, as they have limited browser support, and may change or be removed. However, they can be a suitable alternative in specific cases where no standard option exists.
The fullScreen property of the Window
interface indicates whether the window is displayed in fullscreen mode or not.
Switching between regular window and full screen will fire the "resize" event on the corresponding window.
Value
A boolean value with true meaning that the window is in fullscreen mode and false meaning it isn't.
Examples
js
if (window.fullScreen) {
// it's fullscreen!
} else {
// not fullscreen!
}