send a variable from a popup to a main window

[Maxraid]

I have a page with a link thats opens a popup window, in this the user will upload a image, using php script.

question:

I want a button in the popup, when you click, the popup will close and send the variable(which contains the name of the image)to the main page from where I opened the popup window?

[artacus]

You probably want to fill in a form value. Whatever the case, you reference the original window as document.opener.
In the popup:
[code]
document.opener.getElementById('thing').value = 'whatever';
[/code]