HTML Checking for Large Sites

Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.

There is no attribute validate on the <form> element. Perhaps you meant novalidate?

If the novalidate attribute is present on a <form>, indicates that the form is not to be validated during submission.

For example, while this form has a required attribute on its input, it won’t be enforced because form validation has been disabled using novalidate:

<form novalidate>
  <label>City: <input required name="city"></label>
  <input type="submit" />
</form>

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Related W3C validator issues