ACT Rule 59br37 · proposed
Zoomed text node is not clipped with CSS overflow
This one zooms the page to 200% on a 1280 by 1024 viewport and looks for text that a fixed height and an overflow rule have cut off. Clipped text is the usual way a page fails to survive being made bigger.
A tool can find the places this applies and then hand you the decision. The rule is proposed, so it has not yet been implemented in full by a tool and reviewed by a W3C working group, and the wording can still change.
What passing this rule proves
When this rule fails, 1.4.4 Resize Text 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.
The rule takes one viewport at one zoom level. The criterion asks that text can be resized to 200% without losing content or functionality, at whatever size somebody is actually using. Zoom a real browser and read the page, watching for menus that stop opening and buttons that slide off the edge.
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.
- 1.4.4 Resize Text 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 We link to it rather than restate it, so nothing here can quietly fall out of date against the source.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 59br37 at W3C.
Zoom must not be disabled
Magnifying a page is the most common accommodation there is. Plenty of people with low vision rely on it and use nothing else.
A viewport meta tag can switch that off. It was a common way to make mobile layouts hold their shape. It takes zoom away from everyone who needs it.
user-scalable=no or a maximum-scale set low disables zoom. Usually copied in from an old template without anyone noticing what it does. Users cannot magnify the page.
Fixes that satisfy it
If this rule fails on your site, these are the techniques that put it right.
Other rules W3C files under the same criteria
Each of these asks a different question about the same part of the standard. Passing all of them is still not the same as satisfying the criterion.
- Meta viewport allows for zoom A tool can check this
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.