Skip to main content

Firefox 81 won’t support mozallowfullscreen attribute on iframe element

Mozilla has decided to drop the support for the mozallowfullscreen attribute on the iframe element starting Firefox 81. Although the unprefixed allowfullscreen attribute has been available since Firefox 18, the recently implemented Feature Policy did not take it into account. As a result, mozallowfullscreen stopped working since Firefox 74. Although the bug was fixed with Firefox 80, Mozilla has decided to pull the plug mozallowfullscreen attribute in favor of the current standard for the greater good.

"The HTTP Feature-Policy header fullscreen directive controls whether the current document is allowed to use Element.requestFullScreen(). When this policy is enabled, the returned Promise rejects with a TypeError," Mozilla explains.

"By default, top-level documents and their same-origin child frames can request and enter fullscreen mode. This directive allows or prevents cross-origin frames from using fullscreen mode. This includes same-origin frames."

For now, Firefox 81 is in the Nightly channel. Firefox 79 is Mozilla’s current Stable release whereas Firefox 80 is in the Beta channel. Mozilla will release Firefox 80 Stable on August 25, 2020. 

Source: 1, 2

Related Articles

New Chrome flag finally allows users to create Incognito desktop shortcut

Updated Google Chrome Canary 86 edits Tab Groups faster

Edge 86 will bring SSO for Microsoft Account on macOS, Windows 7/8/8.1