I have a Single Line text field with a simple lookup rule. It "fills" the field with all of the possible data values from the database. The way it behaves is a user starts typing in to the field, and it suggests various possibilities from the database as they continue to type. This works great.

What I want to do is make it so that the field pops an error message, unless the user fills the field with a value that came from that database. There are 10s of 1000s of possible values, so a Drop Down menu is not a reasonable option here.

Is there some mechanism I could use through JQuery or otherwise, that will allow me to prevent submission of the form *and* pop an error message if the value entered in to the field doesn't match one of the suggested values from the database?