Validation is a process of checking documents against formal standards. In addition to yielding maintenance-friendly files, valid markup and code "future proof" files as browsers become standards-compliant.

Validation Resources

Markup Validation Service

The W3C Markup Validation Service checks the markup of HTML documents.

CSS Validation Service

The W3C CSS Validation Service checks your CSS.

HiSoftware Cynthia Says

Cynthia Says check Section 508 or W3C WCAG 1.0 accessibility guidelines.

Link Checker

Use Link Checker to find dead links and fix them.

Web Developer Tools


The Firefox Web Developer Toolbar offers a lots of tools for evaluating file information and structure and for examining pages as they appear with and without CSS, Javascript, images, etc. The toolbar can also be used to evaluate websites for accessibility

Accessibility Testing 

Page Inspectors

Debugging tools built into the browser.


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