Introduction to WAI ARIA : This article is for those who are new to ARIA. You need an understanding of HTML and the potential difficulties that people with disabilities can face...
W3C Link Checker : Check links and anchors in Web pages or full Web sites
PHP_CodeSniffer : PHP_CodeSniffer tokenises PHP, JavaScript and CSS files and detects violations of a defined set of coding standards.
Web Tools for Quality, Accessibility, Standards Compliance.