pop-up menu in web pages in mozilla

Hi! Does anyone know how to use "pop-up menus" in web pages in Mozilla (SuSE 7.0, KDE2, fvwm95)? I mean there are some web sites (eg. search results in www.audiogalaxy.com <http://www.audiogalaxy.com>) where you just step above an icon and then a pop-up menu appeares and you can choose the appropriate action to take from the menu. In windows this works but I still do not know how to set up this in Linux. This is the only thing I simetimes still have to use windows. I think I just have to set up something correctly, don't I? Is this some PHP "mechanism"? Lots of thanks in advance, Denes.