The map links on that page are all to jpg graphics files, so there is no way to get pop-up information at certain places on the screenshots.
Graphical menus in web pages were originally created by splitting an image into rectangular sections and reassembling them in an HTML table, so the web page looked the same as the original, but certain areas of the image could link to other pages, etc. With the development of Flash and Javascript there are easier ways to get mouse-over effects at various 'hot spots' on an image, but they are still much more elaborate than simply providing a screenshot, so in almost all cases there is no effort to replicate the flag information effect on fan sites.