Welcome to the forum aghahamidgol
OK as far as i can work out this uses a shadow layer which contains the pop-ups whose visibility is set to display on click of a button.
In principle it is very very similar to the windows scripts found on this site.
So if you are at the index page () :-
go into Windows scripts () and go to any of the demos there.
The most relevant, and nearest in functionality, is i think is
Of course there are differences; the two main being
1) it has a different skin (to get this you may have to scrimp through the code to find and copy over the server-sideimage(s)).
2) in the goodies example the windows are called with onload function or through a <a href> call. On the other site with a button press.
Hope that is of some help.
Best thing to do is to look at the code of the example aboove (all code contained in mother-file so View Source the page) and see the code for
Create new window dynamically(get data from external file)
PS If you need help with AJAX go to the AJAX tutorial at