WebVenture is a 100% javascript/canvas implementation of the MacVenture game engine. It is still in beta, but the games should be winnable.
It now supports both the mac and IIgs versions of the games.
The mac versions should be stored in HFS disk image format, the IIgs versions
in ProDOS 2mg format.
Save games use HTML5's LocalStorage, so saved games are specific to your
current browser.
Check it out on GitHub
Read the File Format Documentation.
Only tested in Chrome and Firefox. May run slowly in other browsers, or not at all.
There are known bugs in the mac version of Uninvited since it uses the original 1986 Engine, which is slightly different than the 1992 re-issues. If anyone has a copy of the 1992 re-issue of Uninvited, I'd like to hear from you. Contact me at sean at seancode.com.
Update: I was able to get a slightly better copy of Uninvited for mac. It's still not the 1992 re-release, so there are still bugs, but it should be more complete.
Still to be implemented: