Controls Changes in ASP.Net form handle for Save button

Hi All,
I designed ASP.Net form with around 50 controls (C# Code Behind) with Save, Reset buttons in the bottom of Page.  While user editing the form, In case user changes any control values( Either textbox value, dropdown value, or  checkbox values..  any value changes in 50 controls  then only Save button should be enabled. Otherwise Save Button should be disabled. How to handle this in c# code or Javascript code or any other way to handle this page ..please guide me ..
Thanks,
Badri