WYMeditor online demo
WYMeditor 0.2.x is compatible with MSIE 5.5+ and Gecko-based browsers (Mozilla Firefox, SeaMonkey,...).
WYMeditor 0.4.x is compatible with MSIE 6.0+, Gecko-based browsers (e.g. Firefox 1.5+).
Opera compatibility is still experimental. Any help is welcome to improve it.
Updates
The online demo gets updated regularly, so please check it out often.