Change ErrorMessage Text Dynamically

[jdp]

Is there a way to set/change the ErrorMessage and/or Text property of
validationcontrols without making a trip to the server? What I have so
far is a usercontrol that inherits from BaseValidator and overrides the
Pre_Render event in which I have javascript code to do validation. I
also override the AddAttributesToRender event to point to my new
validation function. I'm looking to have a central repository of
error messages so each developer doesn't have to figure one out.

Any feedback would be appreciated.