Why use them?

• Save money
  Most hybrid mobile applications use web based languages/markup Web based developers cost less to employ than native developers
• Save time
  Write one app and build it for each platform (IOS, Android, Windows, etc) No need to retrain developers who already know web based languages

Existing Frameworks:
Ionic, Xamarin, Phonegap, Intel XDK, Framework7, KendoUI, Sencha Touch, Onsen UI