You can add a generic button object at design time and then associate the validations with the click event.
You might also want to force the button when the form is closed as the user might not click it. If it is clean it just closes. If it is not, your warnings will occur.
Thanks for the reply. This sounds like what I am trying to achieve! Please could you explain how to do this? I should have mentioned previosuly that I'm new to livecycle, particulalry anything to do with scriptingc as I have not used this before!
While in LC Designer or Workbench and with the form open, press Shift-F12 to display the Object Library. Scroll down it to the Standard section and pick the "Button" object. Don't pick the "Print Button" or "Submit Button" that may appear before it.
Drag it to your form.
Above your form should be a drag down Script editing area. Drag it down.
Click the button. Click the down arrow in the Script editing area. Click the "Click" event.
Enter the validations you want and save it. Go to the form and click the Preview tab and check that it works.
Really appreaciate the help!