Hi,
The click event of the button probably has a go to next page script. That would work when the user actually clicks it.
You could try a setFocus script for the exit event of the button, which would set the focus to the first object on the next page. This works if the user tabs out of the button without clicking it, then it should fire the exit event.
I am not sure if it will work when the form is viewed in a browser, but it is worth trying.
Good luck,
Niall