HTML and CSS Reference
In-Depth Information
Client-side image maps do not have the same limitations as server-side maps because
they allow you to specify alternate text for each hotspot within the map. For example,
if the image map shown in Figure B-6 were a client-side map, you could make it acces-
sible using the following HTML code:
<img src=”servermap.jpg” alt=”Jackson Electronics”
usemap=”#links” />
<map name=”links”>
<area shape=”rect” href=”home.html” alt=”home”
coords=”21,69,123,117” />
<area shape=”rect” href=”products.html” alt=”products”
coords=”156,69,258,117” />
<area shape=”rect” href=”stores.html” alt=”stores”
coords=”302,69,404,117” />
<area shape=”rect” href=”support.html” alt=”support”
coords=”445,69,547,117” />
</map>
Screen readers or other nonvisual browsers use the value of the
alt
attribute within
each
<area />
tag to give users access to each area. However, because some older
browsers cannot work with the
alt
attribute in this way, you should also include the text
alternative used for server-side image maps.
Tables
Tables can present a challenge for disabled users, particularly for those who employ
screen readers or other nonvisual browsers. To render a Web page, these browsers
employ a technique called
linearizing
, which processes Web page content using a
few general rules:
1.
Convert all images to their alternative text.
2.
Present the contents of each table one cell at a time, working from left to right
across each row before moving down to the next row.
3.
If a cell contains a nested table, that table is linearized before proceeding to the
next cell.
Figure B-7 shows how a nonvisual browser might linearize a sample table.
