How do you add additional functionality to a button added from the answer toolbox?
From the answer toolbox, the Button option adds a plain button to the answer in Design mode. When the button is added, there is no functionality associated to it. The associated HTML code is:
<button type="button">New Button</button>
To include functionality for the button, you must click the Source tab and include appropriate HTML, attributes, and actions. It is your responsibility to add supporting code that executes when someone clicks the button from your published answer.