Image map

In HTML and XHTML, an image map is a list of coordinates relating to a specific image, created in order to hyperlink areas of the image to different destinations (as opposed to a normal image link, in which the entire area of the image links to a single destination). For example, a map of the world may have each country hyperlinked to further information about that country. The intention of an image map is to provide an easy way of linking various parts of an image without dividing the image into separate image files.Server-side image maps were first supported in Mosaic (web browser) version 1.1. Server-side image maps enable the web browser to send positional information to the server about where the user clicks within an image. This allows the server to make pixel-by-pixel decisions about what content to return in response (possible methods are to use image mask layers, database queries, or configuration files on the server).Client-side image maps were introduced in HTML 3.2, and do not require any special logic to be executed on the server (they are fully client-side). They also do not require any JavaScript.It is possible to create client-side image maps by hand using a text editor, but doing so requires web designers to know how to code HTML as well as how to enumerate the coordinates of the areas they wish to place over the image. As a result, most image maps coded by hand are simple polygons.Because the Scalable Vector Graphics (SVG) image format provides its own mechanisms for adding hyperlinks and other, more sophisticated forms of interactivity to images, traditional image map techniques are generally not necessary when working with vector images in the SVG format.