HTML Validator : Welcome

Choose your algorithm

W3C has written two algorithms to check the compliance of an HTML page.
Both algorithms are included in HTML Validator for Firefox. Both have advantages and disadvantages.

For more information, please read the user guide.

HTML Tidy SGML Parser Serial
Description It is an algorithm designed for checking the HTML, XHTML syntax It is the same algorithm, OpenSP, running behind the validator.w3.org. It is a SGML parser based on DTDs. The algorithms execute in the following order: (1) SGML Parser. (2) Then if no error, HTML Tidy
Better for HTML XHTML -
Accessibility check WAI level 1,2,3 No -
Cleanup page Yes No -
Good Help Yes No (Todo) -
Clear error messages Yes No -
Same error as the validator.w3.org No Yes -
Target Audience All Professional Professional