Rocket Validator automatically checks your pages on the W3C Validator.
HTML issues tagged as maximum-scale.
<meta name="viewport"> element has been found where the allowed values for the viewport prevent users from zooming and scaling the document.
user-scalable="no" parameter disables browser zoom on a web page. The
maximum-scale parameter limits the amount the user can zoom. Both are problematic for users with low vision who rely on browser zoom to see the contents of a web page. Consider relaxing these values in order to allow users to resize the documents.
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Keep your sites healthy checking for A11Y/HTML issues on an automated schedule.