HTML Checking for Large Sites

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

The deprecated property longdesc on img elements was used in HTML4 to specify the URL of a text or HTML file which contained a long-form description of the image. This could be used to provide optional added details beyond the short description provided in the title or alt attributes.

Here’s an example from HTML4:

<img
  src="cat.jpg"
  alt="Smiling Cat"
  longdesc="image-descriptions/smiling-cat.html" />

This, however, is no longer valid in HTML5 and can be converted to the following instead:

<a href="image-descriptions/smiling-cat.html">
  <img src="cat.jpg" alt="Smiling Cat" />
</a>

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Related W3C validator issues