Q7) Different Image Maps Styles :

A7) An image map is a graphic image defined so that a user can click on different areas of the image and be linked to different destinations. There are two types of image maps, server-side and client-side maps. Server-side image maps depend on having a special imagemap program running on the web server. They were part of the first generation of web technology and were the only way to hyperlink different regions in an image to different URLs. Now that client-side maps are available, they are more popular.. Client-side image maps can be controlled completely from the browser making them a lot more efficient than server-side maps.

Client-side image maps store the hypertext link information in the HTML document—not in a separate map file as server-side image maps do. When a site visitor clicks a hotspot in the image, the associated URL is sent directly to the server. This makes client-side image maps faster than server-side image maps, because the server does not need to interpret where the visitor clicked. Client-side image maps are supported by Navigator 2.0 and later versions, NCSA Mosaic 2.1 and 3.0, and all versions of Internet Explorer.

Advantages and Disadvantages of Different Types of Image Maps :

There are two advantages to using client side image maps. First, because all the information a client side image map needs to work is loaded along with the image, it works more quickly than server side image maps. Second, an author can test the links in a client side image map locally. This allows one to set up a completely self-contained system without having to have an Internet connection. Client side image maps make it possible to set up links on external drives, CD-ROMS, and other locally networked devices.

Unfortunately, there is one downside to using client side image maps: not all Web browsers support them. Fortunately, it is possible to include code for both client side and server side image maps in the same HTML source file. Combined client/server side image maps automatically default to the user's Web browser's internal map processing capabilities if his/her browser supports them; otherwise, the user's browser accesses the image's external map file to make the image map work.