There are two types of image map. One type is referred to as a server-side image map, which resides on the WWW server. A map is described in a file that is independent of HTML documents. The shape, its coordinates, and the URLs associated with each shape are described in the map file. Formats, however, are dependent on the WWW server program, and each specification is different. Because Homepage Builder supports NCSA and CERN, which are the image map formats of the WWW server program.
The other type of image map is referred to as a client-side image map (hereafter referred to as Client-Side Image Map or CSIM), which is described within HTML documents. CSIM is independent of the type of the WWW server because information on shapes and URLs is described with the HTML syntax, and is processed on the browser side. Management is easy as well because a map can be embedded in the HTML document itself, not in another file. Also, with the CSIM specification, a map is described in an HTML file that is independent of the document itself, and the map can be referenced by specifying a file name and a map name. Homepage Builder, however, supports only the method in which information is described directly in the document.