IFRAMEs Automagically Fit Their Content on iOS

The result of a recent struggle with IFRAMEs on iOS Safari is an interesting discovery: IFRAMEs can expand to fit their (content documents) content without any JavaScript. Even cross-domain! There are two important notes:

Example code:

<iframe width="100" height="100" src="content.html"></iframe>



Click the button and see the magic! Try example code online from your iOS device.

Tested on iOS4 and iOS5, does not work in any other browser I tried. Could not find any relevant documentation on this behavior except a StackOverflow post.