No Standard Full Screen Button for HTML5 <video>?

Question

I have a video element that’s working beautifully with the standard controls in Safari (OS X 10.11 - El Capitan). I have play / pause, the scrubber, captions, and even AirPlay. …but there’s no full screen button. I swear I’ve seen that button on the normal controls before. The WebKit blog even has a screenshot with the button in an unrelated article (backdrop-filter is rad though, check it out).

Is this seriously not standard functionality?

I’ve added fullscreen to the video and source tags and even fullscreen="fullscreen" for good measure. The controls tag is working (I see the controls after all).

iOS’ controls are visually different and include the full screen button.

I’ve been hunting around and the most popular thing I can find is this super old StackOverflow article that basically says I need to use Javascript. That doesn't seem right. I feel like I’m taking crazy pills!

I suppose this could explain why so many sites roll their own controls using the JS hooks but it seems like a lot of work for expected functionality.

I realize I’m just asking for a ding in my pitiful reputation but I hope I’ve just missed something obvious.

Thank you in advance for your help / downvotes. :)

Answer 1

I figured this out, it was at least half stupidity.

Heading

I had the video element set to use max-width: 100% so it would fill the container on the page. I didn't think that would have any effect on the video's ability to go full screen.

No Metadata

The video didn't have any metadata to preload in the first place. I used an app to add a title to the file.

Answer 2

I was in a panic over the problem until I discovered that a <video> contained in a "popup window" instead of a regular window/tab is will cause the <video> tag to drop the fullscreen button in its controls.

My "page preview" happened to be launched in a pop-up window, and having maximized that, it took me a while to eliminate various factors before concluding that it was a popup vs. normal window/tab issue.

The behaviour that I experienced was in Chrome. I haven't tried it with other browsers.

Additionally: Also, note that within IFRAME also behaves the same way, dropping the fullscreen button, too (from the comments).