Zooming and scaling must not be disabled (2x)

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Rule Description

The document must not use the user-scalable=no parameter in the <meta name="viewport"> element because it disables text scaling and zooming which is essential to users with low vision.

The Algorithm, in Simple Terms

Ensures that the user-scalable=no parameter is not present in the <meta name="viewport"> element and the maximum-scale parameter is not less than 2.

Why this is Important

The user-scalable=no parameter inside the content attribute of <meta name="viewport"> element disables zooming on a page. The maximum-scale parameter limits the amount the user can zoom. This is problematic for people with low vision who rely on screen magnifiers to properly see the contents of a web page.

How to Fix the Problem

Remove the user-scalable=no parameter from the content attribute of the <meta name="viewport"> element in order to allow zooming and ensure the maximum-scale parameter is not less than 2.

Compliance Data & User Impact

User Impact: Critical
Disabilities Affected:
  • Low Vision
Issue Type:
  • WCAG 2.0 (AA): MUST
WCAG Success Criteria:
  • 1.4.4 Resize text

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Other Related Resources

Additional Information

Relevant Technologies:
  • HTML 4
  • HTML 5
Test Reliability: Automated testing is possible, with high accuracy
Rule ID: meta-viewport