The best JS library for fullscreen that I've found is https://github.com/toji/game-shim
It's good because it shims the W3C specified fullscreen API; you only have to learn the specified API, you don't have to learn some other API.
It's good because it shims the W3C specified fullscreen API; you only have to learn the specified API, you don't have to learn some other API.
Having the fullscreen request shift to the descendent video also breaks the case where you actually have an element containing a video that you want to make fullscreen, for example if you have custom controls for your video element... This is simply impossible with your API.
It only falls back in the case where that doesn't work (older browser, no allowfullscreen attribute on the iframe) and supports the older API that is just for video tags.