A script for Browser to Add Affiliate Code

I want to Know how i Can Add Affiliate Code To all the Links automatically(to online shopping sites like Flipkart.com ,Amazon India and Amazon US) through A script in a browser. My Retired Uncle Runs a Free Public Library(with always having financial trouble because no one donates), The Library Has few computers which are used many times by people to buy books or other stuff online through Amazon or Flipkart(an indian online shopping Portal). i was hoping to help him by generating some revenue Through those Purchases.

The Affiliate Format that flipkart uses is (assuming affiliate code = Code1)

http://flipkart.com/?affid=Code1 (if "?" has not been used in the url if used the "?" is repaced by "&") other wise "&affid=code1

the Amazon India And Amazon US uses the Same Format but the Affiliate codes are different

please help and tell me whether there is any Extention which i can use for doing the same.

Edit: Iam a totall noob when it comes to coding so please