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Checkpoint 1.2 - Core

All web pages validate to the `DOCTYPE` declaration

WCAG 1.0 Priority 2

WCAG Guideline 3. Use markup and style sheets and do so properly.

Validation of web pages is a process of checking your documents against a formal (X)HTML standard created by the World Wide Web Consortium (W3C). It is similar to spell checking and proofreading for grammar and syntax, but deals with precise programming languages.

Validating to a published formal grammar and declaring that validation at the beginning of a document lets the user know that the structure of the document is sound. It also lets the user agent know where to look for semantics if it needs to.

Requirement

Ensure that all web pages validate to either the W3C's "HTML 4.01 Transitional" DOCTYPE for HTML or "XHTML 1.0 Transitional" DOCTYPE for (X)HTML.

Recommendation

Consult the W3C Markup Validator Help and FAQ pages (validator.w3.org/docs/help.html) for more information on HTML page validation and related information.