How to invoke android core function in webpage with javascript?

I'm trying to learn Html5-ba开发者_StackOverflow中文版sed web application development on android OS. But what confuses me is that can Web APP completely invoke android core feature(such as retriving contacts, sending sms, using various sensors, modifying system settings, etc.), is it possible? Is there javascript framework or some other technology that can do it.

No, that is not possible as it would a serious security problem.