Slider Accessibility

Slider accessibility enables users to select values from a range using keyboard, mouse, touch, or assistive technology. Accessible sliders provide clear value communication, keyboard control, and proper ARIA implementation.

What Is Slider Accessibility

Sliders (also called range inputs) allow users to select a numeric value within a defined range by moving a thumb along a track. Native HTML range inputs provide basic accessibility, while custom sliders require comprehensive ARIA implementation.

Accessibility challenges for sliders include communicating the current value, indicating minimum and maximum bounds, supporting precise keyboard adjustment, and announcing value changes. The visual nature of sliders can make them difficult for non-visual users without proper implementation.

WCAG requirements include keyboard operability (2.1.1), focus visibility (2.4.7), and proper name/role/value exposure (4.1.2). Sliders must be fully operable without a mouse and must communicate their state to assistive technologies.

How Slider Accessibility Works

Native HTML range inputs (input type=“range”) provide built-in accessibility including keyboard support and screen reader announcements. Arrow keys adjust the value. Screen readers announce the role, current value, and value bounds. This native element serves as the foundation for accessible slider implementations.

Custom sliders use role=“slider” with supporting ARIA attributes:

• aria-valuenow: Current value
• aria-valuemin: Minimum value
• aria-valuemax: Maximum value
• aria-valuetext: Human-readable value description when numbers alone are unclear

Keyboard navigation for sliders should include:

• Left/Down arrows: Decrease value by one step
• Right/Up arrows: Increase value by one step
• Home: Set to minimum value
• End: Set to maximum value
• Page Up/Down: Larger increment/decrement (typically 10%)

The thumb element should be focusable and receive visible focus indication. When focused, keyboard input adjusts the value. Visual feedback shows the current position and optionally displays the numeric value.

Screen reader announcements should convey the current value on focus and announce changes as users adjust. Live regions may supplement announcements for value changes during adjustment.

Key Considerations

• Use native range inputs when their appearance can meet design requirements
• Implement all standard keyboard controls for custom sliders
• Provide aria-valuetext when numeric values need description (“50%” or “Medium”)
• Show visual value feedback during adjustment
• Ensure the slider thumb has adequate touch/click target size
• Announce value changes to screen readers during and after adjustment
• Support both discrete steps and continuous ranges appropriately

Common Questions

When should aria-valuetext be used?

aria-valuetext provides a human-readable alternative to the numeric aria-valuenow. Use it when numbers alone do not convey meaning. A volume slider might use aria-valuetext=“50 percent” or “medium volume” alongside aria-valuenow=“50”.

For sliders representing quantities, time, or other numeric values, aria-valuenow alone may suffice. For subjective scales (satisfaction, preference) or units that need context (hours, dollars), aria-valuetext improves comprehension.

How should dual-handle range sliders work?

Dual-handle sliders select a range with minimum and maximum bounds. Each handle operates as a separate slider with its own ARIA attributes. The handles should not cross, requiring logic to constrain movement.

Screen reader users need to understand they are adjusting a range with two values. Clear labeling distinguishes the minimum and maximum handles. Focus order should be logical, typically min handle then max handle.

What step size should sliders use?

Step size depends on the value range and precision needed. A percentage slider might use steps of 1 or 5. A volume slider might use steps of 1-10 out of 100. Smaller steps provide finer control but require more keyboard presses.

The step attribute on native range inputs defines increment size. Custom sliders should calculate value changes based on desired step size. Shift key modifiers can provide alternative step sizes for power users.

Summary

Slider accessibility provides range selection through keyboard controls, ARIA value attributes, and screen reader announcements. Native range inputs offer reliable accessibility, while custom implementations must replicate keyboard navigation, value communication, and appropriate announcements throughout user interaction.