I have make such option via calculation field on FileMaker reflecting to the web via PHP.
Example: Fields A and B cannot be empty
CalcField = Case(is Empty(Field A); "TextA; is Empty(Field B); "TextB";"")
And don't use field validation (not Is empty) for fields.
Thats a great idea! Can you give me an Idea of what the php looks like to display that field?
However, looking into the Filemaker PHP api at the file validation.php it looks like there is some functionality to add the ability to report what field validation failed on...I just don't know enough about php to desipher how to enable it.