User interface components and navigation must be operable. This principle covers keyboard accessibility, timing, seizures, navigation, and input modalities.
Guideline 2.1: Keyboard Accessible
2.1.1 Keyboard Level A
All functionality must be operable through a keyboard interface without requiring specific timings for individual keystrokes. Crucible Scan checks for interactive elements with tabindex issues and elements that may not be keyboard accessible.
2.1.2 No Keyboard Trap Level A
If keyboard focus can be moved to a component, focus must also be movable away using only the keyboard.
2.1.4 Character Key Shortcuts Level A
If keyboard shortcuts use only letter, punctuation, number, or symbol characters, they must be able to be turned off, remapped, or only active on focus.
Guideline 2.2: Enough Time
2.2.1 Timing Adjustable Level A
Users must be able to turn off, adjust, or extend time limits set by content.
2.2.2 Pause, Stop, Hide Level A
Moving, blinking, scrolling, or auto-updating information must have controls to pause, stop, or hide it.
Guideline 2.3: Seizures and Physical Reactions
2.3.1 Three Flashes Level A
Pages must not contain anything that flashes more than three times per second.
Guideline 2.4: Navigable
2.4.1 Bypass Blocks Level A
A mechanism must exist to bypass repeated navigation blocks. Crucible Scan checks for skip-to-content links.
2.4.2 Page Titled Level A
Pages must have descriptive titles. The scanner verifies the <title> element exists and is not empty or generic.
2.4.3 Focus Order Level A
Focusable components must receive focus in an order that preserves meaning and operability. The scanner checks for positive tabindex values that disrupt natural tab order.
2.4.4 Link Purpose (In Context) Level A
The purpose of each link must be determinable from the link text or context. Crucible Scan flags generic link text like “click here,” “read more,” and “learn more.”
2.4.5 Multiple Ways Level AA
More than one way must be available to locate a page within a set of pages (e.g., navigation + search + sitemap).
2.4.6 Headings and Labels Level AA
Headings and labels must describe topic or purpose.
2.4.7 Focus Visible Level AA
Any keyboard-operable interface must have a visible focus indicator.
2.4.11 Focus Not Obscured Level AA
When a component receives keyboard focus, it must not be entirely hidden by other content.
Guideline 2.5: Input Modalities
2.5.1 Pointer Gestures Level A
Multipoint or path-based gestures must have single-pointer alternatives.
2.5.2 Pointer Cancellation Level A
Single-pointer functionality must be cancellable or abortable.
2.5.3 Label in Name Level A
Visible text labels must be included in the accessible name of UI components.
2.5.4 Motion Actuation Level A
Motion-triggered functionality must have UI component alternatives and be disableable.
2.5.7 Dragging Movements Level AA
Drag operations must have single-pointer alternatives that do not require dragging.
2.5.8 Target Size (Minimum) Level AA
Pointer input targets must be at least 24 by 24 CSS pixels.