Disabling iPad/iOS iframe auto-resizing
I had this problem earlier and most questions on StackOverflow were about enabling this, not disabling it, here's a quick fix:
scrolling="no"and give the iframe element a pixel-based width and height, i.e., not 100%.
Recently iOS versions will auto-resize iframes to show their entire content. This is problematic for things like CSS transitions, where elements are intentionally rendered off-screen temporarily.
While this is somewhat a niche thing, there are cases where it is very necessary for
overflow: hidden to be respected, and iOS was bypassing this behavior to show maximum content. Useful in most cases, but otherwise an annoying and underdocumented feature.
Here's another source on the matter.