allowfullscreen is the by far the best HTML attribute in the world! It enables videos from various sources to be displayed in fullscreen mode. Without it, videos would only be visible within iframes, and that would be no fun whatsoever.
The following HTML code, when inserted into a webpage, displays a YouTube video with a fullscreen button:
<iframe width="780" height="428" src="http://www.youtube.com/embed/xDMP3i36naA" frameborder="0" allowfullscreen></iframe>
Here is what the code looks like when displayed to a user. Once the video is played, a fullscreen button is displayed in the bottom-right hand corner:
If by chance you don't agree that allowfullscreen is the best HTML attribute in the world, then please contact us. We need to have a chat ;)
Questions about allowfullscreen
In an effort to create a public forum for allowfullscreen, users can now post questions on our website! We hope to have an exhaustive list of answers to common allowfullscreen issues in the very near future.