Document.fullscreenEnabled - Web APIs
the read-only fullscreenenabled property on the document interface indicates whether or not full-screen mode is available.
... syntax var isfullscreenavailable = document.fullscreenenabled; value a boolean value which is true if the document and the elements within can be placed into full-screen mode by calling element.requestfullscreen().
... example in this example, before attempting to request full-screen mode for a <video> element, the value of fullscreenenabled is checked, in order to avoid making the attempt when not available.
... function requestfullscreen() { if (document.fullscreenenabled) { videoelement.requestfullscreen(); } else { console.log('your browser cannot use fullscreen right now'); } } specifications specification status comment fullscreen apithe definition of 'document.fullscreenenabled' in that specification.

Guide to the Fullscreen API - Web APIs
document.fullscreenenabled the fullscreenenabled property tells you whether or not the document is currently in a state that would allow fullscreen mode to be requested.
...here is the table summarizing the prefixes and name differences between them: standard webkit (safari) / blink (chrome & opera) / edge gecko (firefox) internet explorer document.fullscreen webkitisfullscreen mozfullscreen - document.fullscreenenabled webkitfullscreenenabled mozfullscreenenabled msfullscreenenabled documentorshadowroot.fullscreenelement webkitfullscreenelement mozfullscreenelement msfullscreenelement document.onfullscreenchange onwebkitfullscreenchange onmozfullscreenchange onmsfullscreenchange document.onfullscreenerror onwebkitfullscreenerror onmozfullscreenerror ...
... document.fullscreenenabled the compatibility table on this page is generated from structured data.
...And 3 more matches

Fullscreen API - Web APIs
document.fullscreenenabled the fullscreenenabled property tells you whether or not it is possible to engage full-screen mode.
... document.fullscreenenabled the compatibility table on this page is generated from structured data.
... desktopmobilechromeedgefirefoxinternet exploreroperasafariandroid webviewchrome for androidfirefox for androidopera for androidsafari on iossamsung internetfullscreenenabledchrome full support 45 full support 45 full support yesprefixed prefixed implemented with the vendor prefix: webkitedge full support 12firefox full support 64 full support 64 no support 47 — 65disabled disabled ...
...And 2 more matches

Creating a cross-browser video player - Developer guides
to detect if a browser actually supports the fullscreen api and that it is enabled, the following may be called: var fullscreenenabled = !!(document.fullscreenenabled || document.mozfullscreenenabled || document.msfullscreenenabled || document.webkitsupportsfullscreen || document.webkitfullscreenenabled || document.createelement('video').webkitrequestfullscreen); this simply tests all the different prefixed (and of course the non-prefixed!) booleans to see if fullscreen is possible.
... the visibility of the fullscreen button depends on whether the browser supports the fullscreen api and that it is enabled: if (!fullscreenenabled) { fullscreen.style.display = 'none'; } naturally the fullscreen button needs to actually do something, so, like the other buttons, a click event handler is attached in which we call a user defined function handlefullscreen: fullscreen.addeventlistener('click', function(e) { handlefullscreen(); }); the handlefullscreen function is defined as follows: var handlefullscreen = function() { if (isfullscreen()) { if (document.exitfullscreen) document.

Index - Web APIs
916 document.fullscreenenabled api, document, full-screen, fullscreen api, property, read-only, reference, fullscreen, fullscreenenabled, screen the read-only fullscreenenabled property on the document interface indicates whether or not full-screen mode is available.

Proximity Events - Web APIs
example window.addeventlistener('userproximity', function(event) { if (event.near) { // let's power off the screen navigator.mozpower.screenenabled = false; } else { // otherwise, let's power on the screen navigator.mozpower.screenenabled = true; } }); specifications specification status comment proximity sensorthe definition of 'proximity events' in that specification.

Screen.mozEnabled - Web APIs
syntax let screenenabled = window.screen.mozenabled specifications not part of specification.