shellinabox/html help to insert a keypress with an html button

I am trying to use shellinabox as a terminal emulator. Everything is working except there seems to be no way to simulate an F14 button press in shellinabox. I am already embedding shellinabox in an html page so Im am wondering if there is a way to make an html/js button that will pass F14 to the browser window/shellinabox.

thanks