I recently made a very small jquery mobile web app. It still feels like alpha software, I was on an extremely tight deadline so I persevered with it, the end result worked out ok. I would be interested in other javascript framework recommendations that perform better, however from my research they all seemed to be at a similar stage to Jquery Mobile, either that or they were abandoned. If I was spending a lot of time on a mobile web app I'd probably invest the time into writing it without the layer of abstraction.

Two big tips: 1. Turn off the transitions, they perform poorly and look out of place on most devices. 2. Don't use the navbar, it just doesn't work properly on all devices, I wasted so much time trying to work out the issues with it before changing my navigation scheme.