iwebbrowser2 control

I want you to show me how to call into c++ code from IWebBrowser2 control when a checkbox is enabled in the html view. I have the html and Iwebbrowser2 project. all that you have to show me is how to call into c++ code from javascript inside the html. you need to know win32 and javscript to do this project.

here is the sample c++ project that can load up the html
https://www.codeguru.com/network/display-a-web-page-in-a-plain-c-win32-application/

you need to enhance this project and show how we can call from html that is loaded to c++ code to communicate some information.