is there any possible to develop addons and extesions in asp

Hai all,

 

      i have situation like when i click button in add on (assume my browser is firefox) it will catch the selected value in current page and save it into DB and something..

 

for this i have develop addon  must(client requirement ).time for completing this is 2 weeks (some related issues  are there)

 

now i have question can we develop  these extesions and addons in asp.net

 

if yes where can i get nice3 and complte tutorial

 

i googled but i got nothing but consfuion  

 

Can anyone help me out

 

Thanks and Regards