Sliders

Overview

Sliders select a numeric value or range of values by moving a handle or set of handles along a bar. They are ideal for adjusting settings such as volume and brightness. The slider in its basic form should be accompanied by a label and a number input that doubles as a display for the slider’s current value.

Example range

Disabled range

Usage

Use when

• Encouraging user exploration when setting a value or range of values, especially when that value has an immediate effect on a data visualization.
• A series of options is presented using a stepped slider.

Don’t use when

• Gathering information in a form (e.g, age or salary). Instead, use an Input box.
• Precise amount is needed and the scale is too large to afford precise interaction with the slider.
• Adjusting settings with any delay in providing user feedback.

Specifications

• Always use with a label, even if that label is hidden.
• When a label is visible, it should clearly communicate the purpose of the range input and its values (min, max, step, value).
• Label sliders as optional when input is not required.
• Validate input as soon as users have finished interacting with a field (but not before).
• Always use with two text field components when range slider has dual thumbs to provide accessible alternatives to both the lower and upper thumbs.

Behaviors

• Adjust a slider’s value(s) by clicking and dragging its handle(s), or by clicking anywhere on its bar.
• Hovering over an active slider’s handle will change the default cursor to the grab cursor; clicking will change it to the grab cursor.
• Changes made with sliders are immediate.

Accessibility

• The element serving as the focusable slider control has role slider.
• The slider element has the aria-valuenow property set to a decimal value representing the current value of the slider.
• The slider element has the aria-valuemin property set to a decimal value representing the minimum allowed value of the slider.
• The slider element has the aria-valuemax property set to a decimal value representing the maximum allowed value of the slider.
• If the value of aria-valuenow is not user-friendly (e.g., the day of the week is represented by a number) the aria-valuetext property is set to a string that makes the slider value understandable (e.g., “Monday”).
• If the slider has a visible label, it is referenced by aria-labelledby on the slider element. Otherwise, the slider element has a label provided by aria-label.
• If the slider is vertically oriented, it has aria-orientation set to vertical. The default value of aria-orientation for a slider is horizontal.
• Make sure the thumb is in the page tab sequence.
• Right and Up arrows increase the value of the slider by one step; Left and Down arrows decrease the value of the slider by one step.
• When using a multi-thumb slider, each thumb is in the page tab sequence and has the same keyboard interaction as a single-thumb slider.