.NET: unmodified WebUIValidation version mismatch!
So the hacking of the WebUIValidation code continues. But low and behold, my WebUIValidation.JS didn't match the one on the server. I found this odd, because they both are in the aspnet_client\system_web\1_1_4322 folder. But the live site's version had a function which returned a value, where my own did not. I never touched that code, so lesson is: Use your diff tools!! :) Evidently 1_1_4322 doesn't exactly mean you're dealing with the same build, after all!