evaluating the accessibility of rich internet applications

Evaluating the accessibility of Rich Internet Applications

Nádia Fernandes, Daniel Costa, Sérgio Neves, Carlos

Duarte, Luís Carriço

W4A 2012 – Accessible Web 2.0

Motivation

• The Internet has become an indispensable tool for our everyday life

• And it is used by all kind of people

– With different physical and/or mental capabilities


• The content of Web pages must become accessible to all users

• Developers need a way to help them implement an accessible page

• Tools should be provided to enable evaluation of the accessibility

Problems


• The Web Content Accessibility Guidelines (WCAG)– A set of best practices for developing an accessible

Web page

• Automated accessibility evaluators– QualWeb (Nádia et al)

– Achecker

– And more…

Solution


• Web pages are no longer static content displayers

• With the Web development, Rich Internet Applications are becoming a trend

• New elements are introduced on the Dom tree triggered by javascript functions

New Challenges


• QualWeb 3.0

– New WCAG techniques evaluated (including CSS techniques)

– Added a new module that triggers and observes changes made on the Dom tree

New approach


Architecture


• This component is responsible for activating interactive elements in the HTML document– For each interactive element it is attached a

function (Crawler) that triggers this element periodically

– At the same time there is an Observer which analyses the Dom tree to see if it has changed

– A change in the Dom tree is considered a new state of the RIA

Interaction Simulator


• The evaluator receives the new state and performs the evaluation

• 20 HTML WCAG 2.0 and 6 CSS WCAG 2.0

• Then generates an EARL report

QualWeb evaluator


• 5o inspiring Web applications

– http://speckyboy.com/2009/09/02/50-inspiring-web-application-and-service-web-site-designs/

Experimental study


Goal

• The goal of this experiment is to validate this new approach

• Understand if it is possible to automatically trigger changes on the Web page

• Understand if those changes affect the accessibility of the page


Results


• There was an average of 5 different states per page– The number of fails and warnings increased 4% and

10% in comparison with the original state

• In this experiment the average of pass results is 28% , fail results represent an average of 12% and 60% for warnings.

• 43% of the Warning results come from the CSS evaluation

Results


Advantages

• The main advantages are:

– The evaluation is made on browser environment

• VS “Offline” evaluation

– Evaluates WCAG 2.0 techniques (HTML and CSS)

• VS WCAG 1.0

– Can evaluate parts of the Web page that were otherwise unreachable


• The results obtained show that it is possible to evaluate automatically states that can be triggered without human intervention

• We demonstrated that there are differences when evaluating different states of the Web page

• We have developed a more complete evaluation of Web pages

Conclusions


• Implement more WCAG 2.0 techniques

• Perform more tests

• Remove some limitations we had

Future Work


• Daniel Costa – [email protected]

• Nádia Fernandes – [email protected]

Questions?


evaluating the accessibility of rich internet applications

Design