How can I send an event from child window to its parent window

Question

My main goal is:

Going to my application, open a link there in a new tab, make something in the new tab and send an event to the parent-main tab to refresh.

Answer 1

What I did for myself, I implemeted some ajax to submit changes from the window2 into database. I implemeted JSON to pull new data from the database back to window1