Depends on the library used. I've built mobile apps wrapped in Cordova/Phonegap where performance was acceptable so long as I stayed away from things like JQuery Mobile that adds a lot of overhead and stuck with the Cordova API's and plain ole javascript...
What you want is called Apache Cordova, formerly PhoneGap. This will allow you to easily turn your HTML5 app into native apps for iOS, Android, Windows Mobile, Blackberry, and other platforms.
http://jumpgate-tri.org is another game based on the old jump gate MMO. Easy to get up and running, is an MMO with near neutonian physics, but no 6DOF and more WWII in space, but not so much drag...