how to check if user made any changes on a webpage

On one of my web page, there are around 40 controls (textboxes, dropdownlists, and radio buttons). 
When a user clicks on the "go to next record" button, I would like to check if any text in the textbox was changed,
or if any selection in the dropdownlist/radiobutton was changed.
 
I only have two ways to do it now.
1. record the original values of each controls and compare the new values with the old values when click on the button,
this will be very tedious and sounds not smart.
 
2. make each control postback and fire the "text_changed" event for textboxs, "selection_changed" event for dropdownlists/radio buttons.
this will slow down the process and users will hate the slow speed.
 
Any suggestions?
...