Yes, it is possible. I believe your question is already answered and links to external resources are provided within the following SO questions:
How to call Objective-C from Javascript?
How to invoke Objective C method from Javascript and send back data to Javascript in iOS?
Invoke method in objective c code from HTML code using UIWebView
Disclaimer: I am not sure if this qualifies as an answer, but it seems my reputation does not allow me to write comments, so here we go.