On iOS, a line like:
won't produce a scrollable iframe having the height specified above, but an iframe whose height is automatically adapted to its contents. What scrolls, then, is not the iframe on the page, but the page itself.
<iframe src="http://www.dynamicdrive.com" style="position: relative; width: 300px; height: 300px" frameborder="0"></iframe>
There's a way to force iOS to behave like you would expect. All you have to