How do i know that additional_shipping_cost updated (Backoffice product)

[ArsalanAnsari]

Hi,

Actually i am trying to create a backoffice module and according to my need's i want if we modify additional_shipping_cost and click save or save and stay button then how do i know that additional_shipping_cost has updated?

because i wish to execute that module only if additional_shipping_cost goes update.

 

Hope that its clear.

Thanks in advance.