Web Accessibility Evaluation Via XSLT

Abstract

Web accessibility rules, i.e., the conditions to be met by Web sites in order to be considered accessible for all, can be (partially) checked automatically in many different ways. Many Web accessibility evaluators have been developed during the last years. For applying the W3C guidelines, their programmers have to apply subjective criteria, thus leading to different interpretations of these guidelines. As a result, it is easy to obtain different evaluation results when different evaluation tools are applied to a common sample page. However, accessibility rules can be better expressed formally and declaratively in rules that assert conditions over the markup. We have found that XSLT can be used to represent templates addressing many accessibility rules involving the markup of Web pages. Even more, we have found that some specific conditions relaying in the prose of the XHTML specification not previously formalized in the XHTML grammar (the official DTD or XML Schemas) could also be formalized in XSLT rules as well. Thus, we have developed WAEX as a Web Accessibility Evaluator in a single XSLT file. Such XSLT file contains 70+ singular accessibility and XHTML-specific rules not previously addressed by the official DTDs or Schemas from W3C.