I am trying to develop in Firefox Os, but which is the best (fast, structured) framework for that. I try with Sencha Touch, but unfortunately It doesn't work with firefox yet.
Any suggestion?
All frontend frameworks that support Firefox work on FxOS. AngularJS, Backbone, etc should bring you the view abstraction you need.
More options are being released, like Lungo, an HTML5 app and component framework. jQuery Mobile is another UI-component framework working well on Firefox OS.