Script to validate mandatory fields, check total in a table, and return "success" message box

I need help writing a script for a button in LiveCycle designer.

I need the button to validate mandatory fields. If they aren't filled in, highlight them and give an error message that fields need to be completed.

The button should also check a total that is calculated in a table and confirm it's = 100. If not, highlight the error and give an error message to adjust numbers on the table so the total = 100.

If all fields are completed, show a message that says "all fields are completed."