Dave Hyatt – the core developer for Apples WebCore that drives the HTML rendering engine of Safari – is leaking some details:
The new WebCore also supports HTML editing. You can specify editable regions in a page using the contenteditable attribute (which maps to a CSS property behind the scenes, so you can even set that property in your user stylesheets if you want to get crazy). …
The support for the contenteditable attribute was available in Internet Explorer for Windows since version 5.5. It was never part of the W3C HTML specification. So Mozilla developers rejected to implement it (here is an article by Tim Powell on that matter; also Scott Andrew comments).
There was a long discussion about TTW (“Through The Web” editing) and there have been numerous attempts to solve this issue. The adoption rate has been very low. I don’t know the reason for it, but judging from my own experiences with these applications most of them are clumsy and the resulting HTML code is ugly and hard to debug.
I understand the Mozilla developers insisting on the standards. But I’m also tired of waiting for features that everyone needs (it’s not a marquee tag!).