Currently I have a form that members can submit data into. After they submit the form I need to verify "some" of the data exists, and is valid, before proceeding. If that data is invalid, or non-existent, I need to show them an error. How can process the data, via AJAX, and give them the "please correct the following errors" popup? Also, in case it matters, none of this data is being written into the database "as is".