How to read webkitAllowFullScreen attribute in iframe using javascript

Question

For the following iframe code:

<iframe src="testA.html" webkitAllowFullScreen mozallowfullscreen allowFullScreen></iframe>

Inside testA.html, how do I tell if the webkitAllowFullScreen attribute is included using javascript?

Answer 1

If the allowfullscreen attributes are added to the iframe the variable below should be true

var fullscreenEnabled = document.fullscreenEnabled || document.webkitFullscreenEnabled || document.mozFullScreenEnabled;

This even works when the iframe src is on a different domain.
Note: the letter s in fullscreenEnabled is uppercase for Firefox

Answer 2

This is the most robust solution:

if(window.frameElement && window.frameElement.hasAttribute("webkitAllowFullScreen")){

}

It utilizes window.frameElement, which returns the DOM node of the parent framing element, which you can then make a hasAttribute call against.