The button below is added to the page like this:
<center><wxp module="wx.lib.platebtn" class="PlateButton" width="50%"> <param name="label" value="It works!"> <param name="id_" value="ID_OK"> </wxp></center>
Notice that the button click event is actually caught by the panel that contains this window, which then logs it in the window below.
This is the same widget reused three times, each with a different parameter value. Source code is here.
Recognize this one?
You can also embed other wxHtmlWindows!