Detecting clicks on an html viewer

My app displays an html viewer which loads an external web page (that I have no control over) that in turn displays two buttons. I would like to know which button the user clicked. How would I go about that?

Depends on the buttons… You can always check the URL parameter of the CancelLoad event if they are used to go to another page… Anything beyond that, I just inject my own JavaScript to trigger methods in Xojo…