HTML Checking for Large Sites
Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.
HTML issues tagged as main.
Example of 2 main elements, where only one is visible:
<main> <h1>Active main element</h1> <!-- content --> </main> <main hidden> <h1>Hidden main element</h1> <!-- content --> </main>
The main element represents the dominant contents of the document, so it should not be contained within another section.
A document must not have more than one main element that does not have the hidden attribute specified.
A hierarchically correct main element is one whose ancestor elements are limited to html, body, div, form without an accessible name, and autonomous custom elements. Each main element must be a hierarchically correct main element.
The main landmark role is used to indicate the primary content of a document. It can be added to an element by using role="main", but instead it’s preferable to just use the <main> element. In that case, it’s unnecessary to make the main role explicit. Examples:
<div role="main"> <!-- this is a valid way to define a main role --> </div> <main> <!-- but this is shorter and uses correct semantic HTML --> </main>
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