usemap Attribute

Where to use the usemap Attribute

• As Type IDREF:
  usemap is declared on the elements: object, img, input type="image"

Description

The usemap attribute is a Boolean attribute declared by the Client-side Image Map Module and specifies the id attribute of a map element to use as a client-side image map (see the Client-side Image Map Module page for details)

IMPORTANT UPDATE: It seems as though browser support for valid XHTML 1.1 client-side image maps (CSIMs) is actually quite poor. In 2007, my testing led me to believe that major XHTML-compatible browsers would automatically interpret usemap attributes correctly (i.e. as having the IDREF attribute type) provided that the XHTML 1.1 document was served as "application/xhtml+xml". However, it seems as though newer browser releases use the old HTML URI fragment identifier method irrespective of the MIME type sent by the server. For example, I found that Firefox 2 recognised usemap as having type IDREF and hence behaved as expected. On the other hand, Firefox 3 (and Opera 9.5, for that matter) renders usable CSIMs only if usemap is assigned a URI fragment identifier, even if the "application/xhtml+xml" Content-Type is specified. This makes it impossible to write valid XHTML 1.1 CSIM code which will function in these browsers. I would therefore recommend that CSIM code be avoided in XHTML 1.1 documents.

See also the ismap attribute.