Firefox’s incorrect implementation of
padding on the
<textarea> element has been fixed to resolve a longstanding browser compatibility issue, as this screenshot shows. Now
padding spaces are added inside the scrollbar and resizer controls, instead of outside, to match with the CSS spec and other browsers’ behaviour.
padding will be included in the
scrollHeight properties of the element. A side effect of this change has been found on eBay where the height of a message textarea is programmatically expanded while typing.