Validate by date calculation?

[Bill_B]

Ok, I am pretty new to this. But my question is this, after entering a date into a field, if the Get(CurrentDate) is less than the entered date in the field, I would like to initiate a custom dialog(I can do this) and then reformat the text color. I have been unable to accomplish this using the scripts, I am pretty new to the scripting here. I need an example, then I am off. Thank You