Wikimedia Bugzilla is closed!

would it be possible to get a wordpress.org style instant preview feature? An
example is visible here: 
http://www.ektopia.co.uk/ektopia/archives/2004/06/14/aerogel
Just type into the text box, any html code is instantly transformed in the
browser. Aw MAAAAN we gotta have THAT!

Syntax errors would be instantly visible and would not require a preview, a
change and a second preview to get it right. It thus takes resources off the server.
The limitation would be that only syntax (and NOT links inside [[double
brackets]], et al) would be instant and the rest would obviously require a
preview to render visible.

This could also be toggled on and off, as some would find it redundant to have
both types of previews.

The way I envision it ideally working is as an instant preview of only the lines
of the document above and below the cursor at any given moment, but perhaps this
too could be set in the preferences.