Trap display form events

I have a display form, with multiple textboxes, checkboxes. I want to have the ability to trap the event when a checkbox is turned on or off, from which I can then turn on a particular layer on the map.

Another example is when a autocomplete box is used, I would llike to have the ability to trap the event when I pick the selected record from the dropdown, I can then have the ability to zoom to that feature or only display that feature.

At the moment I can only run the workflow by clicking on a button, but having that dynamic feel, would make it a better user experience for the user.

Halil