HTML Checking for Large Sites

Rocket Validator automatically scans your sites for accessibility issues using the W3C Validator, hosted on our own servers and integrated into our web crawler.

When was the last time you validated your whole site?

Keep your sites healthy checking for A11Y/HTML issues on an automated schedule.

A document must not include more than one visible “main” element.

There can only be one visible <main> element in a document. If more are needed (for example for switching between them with JavaScript), only one can be visible, the others should be hidden toggling the hidden attribute.

Example of 2 main elements, where only one is visible:

  <h1>Active main element</h1>
  <!-- content -->

<main hidden>
  <h1>Hidden main element</h1>
  <!-- content -->

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Related W3C validator issues

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