ACT Rule b33eff
Orientation of the page is not restricted using CSS transforms
Some pages lock themselves to portrait or landscape by rotating the whole thing with a CSS transform. That fights anybody whose tablet is mounted to a wheelchair and cannot be turned. This rule finds the transform.
A tool can decide this one on its own, which is why it turns up in scanner output. The rule is approved, which in W3C's process means it was implemented in full by at least one tool or methodology and then signed off by a working group. Approval is a statement about tools, not a statement that this is the settled way to test the criterion.
What passing this rule proves
When this rule fails, 1.3.4 Orientation is not satisfied, and that half is certain. When it passes, W3C's own outcome mapping says the criterion still needs further testing. So a green result here is evidence that one specific thing is not broken, and it is the answer W3C gives on 59 of its 87 live rules.
CSS transforms are one way to lock orientation and not the only one, and W3C says the rule does not consider scripts that do the same job. So turn a real device and watch. Then decide whether any locking that remains is essential, which is the one exception the criterion allows.
The criteria this rule is a test for
These are the criteria the rule names as its own conformance requirement. Each one is a far bigger question than this rule asks, and our page for it sets out what the whole criterion covers.
- 1.3.4 Orientation Level AA
The normative rule text lives at W3C
What the rule applies to, and exactly what it expects, is published by W3C and can change. We link to it rather than restate it, so nothing here can quietly fall out of date against the source. Read rule b33eff at W3C.
Pages must work in both portrait and landscape
A page must work in portrait and in landscape unless the orientation is genuinely essential, which is rare. Someone whose device is fixed to a wheelchair mount cannot turn it.
Locking orientation takes their choice away and leaves them with a layout they cannot use.
A CSS transform that rotates the page to force one orientation or a lock inherited from an app wrapper prevents users from turning their device. The layout breaks and becomes inaccessible.
Fixes that satisfy it
If this rule fails on your site, these are the techniques that put it right.
All 87 ACT rules are grouped by the criteria they test, and 24 of them decide nothing about WCAG on their own. Run a free scan to see which of these your own pages trip.