I used a Button builder and set that in the Post-Action Behavior. The issue that I had was when submitting, the button stays active. If the connection is fast, it does not matter but when I was working at a slow connection place, when submitting, it takes a few seconds before the Thank you page shows but the button is still active.
The button calls an action. I want the button to run additional Javascript before running the action. From the forum, I manage to find the solution.
The HTML Event Action can be used. Select the location you want to insert the javascript. Action type, I use "Run a script". Then put in the javascript. In Advance, use Prepend new value.
This is very useful to add in more actions before the button action is triggered.
