Server-side image maps must not be used
Compliance Data & Impact
Disabilities Affected
- Blind
- Deafblind
- Mobility
Requirement(s)
Section 508: MUST
WCAG Success Criteria
2.1.1 Keyboard
Section 508 Guidelines
1194.22 (f) Client-side image maps instead of server-side
Rule Description
The document contains an image map that is server-side instead of client-side.
Why it Matters
Server-side image maps are not keyboard accessible; mouse clicks are required to access the links contained in the image, making the image inaccessible to people who only use keyboards for their navigation.
Server side image maps pass the coordinates of the mouse click to the server-side script used to process the image map. Because they rely on mouse clicks, they are not keyboard accessible, whereas client-side image maps are keyboard accessible. Further, it is not possible to provide text alternatives to the actionable areas of a server-side image map like you can with the areas of a client-side image map.
How to Fix the Problem
Change all server-side image maps to client-side image maps.
Bad Example
Don’t use server-side image maps.
<a href="/maps/nav.map"><img src="/images/navbar.gif" ismap></a>Good Example
A client-side image map is contained by an <img> element. They have a usemap attribute containing the name of the image map (i.e. <img usemap="myImageMap" src="..." >). After the <img> element, a set of <map> elements encloses the space where clickable hotspots are defined on the map as follows:
<img src="images/solar_system.jpg" alt="Solar System" width="472" height="800" usemap="#Map"/>
<map name="Map">
<area shape="rect" coords="115,158,276,192" href="http://en.wikipedia.org/wiki/Mercury_%28planet%29" alt="Mercury">
<area shape="rect" coords="115,193,276,234" href="http://en.wikipedia.org/wiki/Venus" alt="Venus">
Remaining hotspots in image map...
</map>The Algorithm (in simple terms)
Ensures that server-side image maps are never used.