Is there a way to do the following in php or javascript?

Here's the problem

I have a main window from which i am submitting a form using POST, which submits the same to a popup window. The popup window then traverses through a few links LINK A -> LINK B -> LINK C -> LINK D. So, how do i send back a response (boolean variable) from LINK D to the main window. Is this possible using php or javascript or both, if so, what components should i use and how do i do it ?

Thanks in advance