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Accessible Web Design
 Accessibility
means that a website should be designed
so that people with vision or hearing
difficulties can still access the information
within a site. In the case of this website,
there is no sound, so our primary focus
is on visual aspects. Visual difficulties
cover a wide range of problems, ranging
from a simple inability to read small
or large text to complete lack of vision.
Solutions used to overcome these situations
include allowing the user to change the
font size, to the use of software that
reads aloud everything on the page (known
as 'screen readers') to hardware devices
that can translate the screen image into
Braille.
In an increasing number of countries, there
are laws which state that any publicly-accessible
website must not offer content on the
web that a person with disabilities cannot
access. So for example, if you have a
page with a competition entry form that
is built in Flash, which screen readers
cannot read, then you are effectively
discriminating against people with poor
vision.
Controlling Font Sizes
The major browsers offer a facility for
the user to set a larger or smaller font
size. In Internet Explorer 5 and above,
you can quickly do this by holding down
the Control key and moving your mouse
wheel (if you have one) up or down. In
Netscape 6 and above, press Control and
+ or -. You can also change font size
from the browser menu (in both IE and
Netscape go to view > text size).
Contrast
We could not find any definition of what
constitutes an acceptable level of contrast,
however the principle is that there should
be sufficient difference between the colour
of text and the background colour behind
it to make reading easy. A particular
point to watch out for is in the use of
coloured text and backgrounds - blue text
on a green background, for instance, might
not be legible at all if a person has
limited colour perception (a good test
of contrast is to print a page in black
and white).
Standards
There are several sets of standards relating
to website accessibility. The core concept
in designing accessible web pages is the
proper use of HTML and CSS - adhering
to the standards makes it fairly straightforward
for various devices to interpret pages.
For example, most web designers use tables
to create page layouts - but in HTML the
only correct use of a table is to present
tabular data.
The World Wide Web Consortium (W3C) offers
a set of guidelines as to how Cascading
Style Sheets may be used to control page
layout to generate an attractive layout
without using tables. For more information,
go to http://www.w3.org/TR/WCAG10/full-checklist.html.
The US Rehabilitation Act Section 508 lays
down legal guidelines for sites developed
for US Government Agencies (it does not
apply to non-Governmental organisations).
http://www.section508.gov/.
Bobby
 Bobby
is a piece of software that can analyse
any web page and produce a report that
highlights any problems for the disabled.
To check a single page, go to http://bobby.watchfire.com/bobby/html/en/index.jsp.
Here you can type in the URL of the page
and receive an instant analysis of it.
Bobby addresses 3 levels of accessibility,
and its report indicates definite errors
and 'maybe' errors for each priority level.
The 'maybe' errors are things that the
Bobby software cannot make a judgement
on - it requires a human to decide. Bobby
is a self-certification system. For this
entire site we claim a 'triple A' rating,
the highest possible: we'd love to hear
from you if you find any reason to disagree
with this claim!
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