"Relaxed" is an HTML validator implementation as well as a XHTML 1.0 / HTML 4.01 and WCAG 1.0 schema definition written in Relax NG with embedded Schematron patterns. Those modern and expressive languages allow automated validation of many additional restrictions which cannot be expressed using DTD (used e.g. in W3C Validator). Using "Relaxed" validator may help authors of HTML documents to adhere better to commonly recognized standards and thereby improve the accessibility of those documents and the usability of this technology in general.

"Relaxed" thesis text


What is Relaxed Firefox extension?

This extension provides HTML validation based on "Relaxed" directly inside your browser. The extension doesn't include "Relaxed" run-time so an internet connection is necessary to send HTML to Relaxed service for validation.

Features of plugin

  • number of errors is shown in the status bar
  • error details are ordered in a table in the HTML source
  • error highlighting in the HTML source
  • line numbers in the HTML source (only in Windows)
  • possibility to choose domains to validate
  • supported browsers:
    • Firefox 1.0+
    • Flock 0.7+
    • SeaMonkey 1.0+
    • Mozilla Suite 1.7+
  • supported OS:
    • Windows
    • Linux

How to install extension?

Simply click on this link in Firefox. After choosing download mirror Firefox will ask you whether you want to install this extension. (If not, then please save the downloaded file to disc and then open it manually in Firefox.) You must restart Firefox prior using extension.


Jaroslav Hanslík