ACT Rule akn7bn
Iframe with interactive elements is not excluded from tab-order
An iframe with a negative tabindex is taken out of the tab order, and everything inside it goes too. A perfectly good button inside that frame becomes unreachable by keyboard. This rule finds iframes that have been excluded while still holding focusable content.
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, 2.1.1 Keyboard and 2.1.3 Keyboard (No Exception) are 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.
This is one specific way keyboard access breaks. The criterion asks whether all functionality is available from a keyboard, which takes in custom widgets, drag and drop, hover menus and anything driven by a mouse event with no keyboard equivalent. Unplug the mouse and try to buy something.
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.
- 2.1.1 Keyboard Level A
- 2.1.3 Keyboard (No Exception) Level AAA
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 We link to it rather than restate it, so nothing here can quietly fall out of date against the source.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 akn7bn at W3C.
Focus must be visible, reachable and escapable
Keyboard users move through a page one stop at a time. Three things have to hold at every stop. You can see where you are, you got there in an order that matches the page, and you can leave again.
Break the last one and you create a keyboard trap. The person cannot go forward, cannot go back. Their only way out is to close the tab and lose whatever they had entered.
Custom widgets and modals cause most of these. A dialog that takes focus but never returns it leaves keyboard users stuck inside it with no way out except closing the entire tab.
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.
- Scrollable content can be reached with sequential focus navigation 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.