Written by Aravind H.U on Aug 6, 2014
Before starting to explain Accessibility principles, Let me list down some questions which came to my mind and made me to learn this.
why should we make our web application accessible ? Is it possible for a web application to be in accessible ? Is there any part/module of your application cannot be accessible ?
For all these questions the answer is simply "NO", Because web 2.0 applications often exhibit a value called Ownit when it is served to client machines . I meant, when a web application is loaded in clients browser, then its owned by User, he can save/share/writedown/read OR can do what ever he wants with that, Worst case you can prevent replication using copyrights.
The whole set of accessibility principles are applied to address accessibility issues of the people who are suffering from some disabilities, Disability can be visual, auditory, speech, or some birth defect or some impairment caused due to ageing.
Let me make a disclaimer before explaining these principles, You can never ever make your application accessible to all sorts of people, Hence I always suggest/prefer defining the target audiance of your application before building it. Since making an existing application accessible might be costly or might impact the functionality of your application .
This also doesn't mean, web application accessible for people with disability cannot be accessible by normal people. I just meant, things accessible for people with disability will always be by default accessible for normal people :) .
Government of United states, had come up with Section 508, in 1998, which was enacted to eliminate barriers in information technology, It was an ammendment to rehabilitation act of 1973. This is applicable only for federal agencies.
The subpart B of section 508 talks about technical standards, and it also defines 16 rules for Web-based intranet and internet information and applications.
To know the 16 rules, you can refer to the section document at section508 website.
Offcourse this is just an initiative by US govt, to eliminate barriers in Information technology, when it comes to globalization of accessibility standards, W3C has come up with an initiative called web accessibility initiative, they published web content accessibility guidelines ( WCAG ) in 1999.
Most of the countries which has E-governance in place does not have there own standard like section 508 but all this countries relay on WCAG .
Currently version 2.0 of WCAG guidelines are available and stable, most of the websites today follow 1.0 guidelines .
To know the differences between 2.0 and 1.0 please refer to WCAG documentation on differences.
WCAG 2.0 has four main principles : -
I donot need to discuss each of them, because the WCAG documentation has the best explaination, please go to through the hyperlinks to learn more about each of them .
You can also refer to Complete W3C documentation of WCAG 2.0 from W3C website .