HTML Checking for Large Sites
Rocket Validator automatically checks your pages on the W3C Validator.
Attribute “X” not allowed on element “Y” at this point.
An invalid attribute has been found on an element. Check the affected tag to ensure attributes are well-formed, and if they are you can consider using custom data attributes.
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Related W3C validator issues
The attribute displayText is not allowed on <span> elements.
This issue is commonly caused by an old integration of ShareThis via Drupal or other CMS - the old code used invalid attributes like displayText, st_url and st_title which were later changed to HTML5 custom data attributes.
Learn more:
- [ShareThis: how to migrate legacy buttons(https://sharethis.com/support/installation/migrate-from-sharethis-legacy-buttons-to-inline-buttons/)
- Drupal: W3C validator issues on st_url
- MDN: using data attributes
The <table> element does not accept a height attribute. Use CSS instead.
Check the syntax of the affected tag, it’s probably malformed and a < character inside has been interpreted as an attribute.
For example, this code might cause this issue:
<!-- Malformed img tag -->
<img src="photo.jpg" alt="smiling cat" < />
<!-- Fixed img tag -->
<img src="photo.jpg" alt="smiling cat" />
The attribute st_title is not allowed on <span> elements.
This issue is commonly caused by an old integration of ShareThis via Drupal or other CMS - the old code used invalid attributes like displayText, st_url and st_title which were later changed to HTML5 custom data attributes.
Learn more:
- [ShareThis: how to migrate legacy buttons(https://sharethis.com/support/installation/migrate-from-sharethis-legacy-buttons-to-inline-buttons/)
- Drupal: W3C validator issues on st_url
- MDN: using data attributes
The attribute st_url is not allowed on <span> elements.
This issue is commonly caused by an old integration of ShareThis via Drupal or other CMS - the old code used invalid attributes like displayText, st_url and st_title which were later changed to HTML5 custom data attributes.
Learn more:
- [ShareThis: how to migrate legacy buttons(https://sharethis.com/support/installation/migrate-from-sharethis-legacy-buttons-to-inline-buttons/)
- Drupal: W3C validator issues on st_url
- MDN: using data attributes
An attribute could not be parsed from the HTML input, probably due to a typo. Check this guide for a related HTML issue.
Quote characters used for attributes can use either single quotes (') or double quotes ("), and they must be properly matched, for example:
<p class="news">...</p>
A common cause for this issue is forgetting to use the equal sign (=), so the HTML parser wrongly believes the quote forms part of the attribute name, for example:
<p class "news">this is wrong</p>
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