I had to email the snippet to myself since Martin Kool's textarea did not show up on my phone. I haven't tested this technique in any device other than iPhone, but it should work.
For anyone unfamiliar with Firebug, it is a web developer's must have. Unless, of course, if Safari or Chrome's developer tools fit the bill for you. They don't for me first of all because Firebug was around first and I got used to it, second because it has better features, and last because it is easier to use.
(Yet, unfortunately, Firefox has become absurdly memory intensive which makes it difficult to develop with. Chrome is a much better browser in that regard.)