jsFunge IDE is a Befunge 93 editor, interpretor and debugger. It is written in XHTML, CSS and Javascript, so it can be used online, or it can be downloaded for using it offline.

For the moment, it only works with Firefox (3.x or higher), but it will be compatible with webkit based web browsers (Chrome, Chromium, Safari,...).

Use it online: http://befunge.flogisoft.com/