OpenA11y Evaluation Library

Value in range

Rule ID Widget 10
Conformance Required
Definition Range widget must have value between minimum and maximum values, or have an indeterminate state.
Purpose
  • Range roles identify a value between a minimum or maximum value and whether the value can be changed by the user (e.g. scrollbar, slider or spinbutton).
  • Screen readers typically render the value of a range widget as a percentage of the total range defined by the minimum and maximum values.
  • Elements with the role separator that are focusable (e.r. tabindex=0) are considered a range role with the same requirements as a scrollbar.
  • aria-valuetext can be used to render an alternative to the percentage when a numerical values and/or a units of measure are more descriptive.
  • Some range roles (e.g. progress and spinbutton) allow an unknown current value indicating indeterminate or no current value.
Conformance Required
WCAG Success Criteria

Success Criterion 4.1.2 Name, Role, Value

Other Related Success Criterion:

Rule Category ARIA Widgets
Rule Scope Element
First Step no
Techniques
  • Use the numerical value of the aria-valuenow attribute must be in the range defined by aria-valuemin and aria-valuemax.
  • Screen readers typically render the range value as a percentage, requiring a valid aria-valuenow attribute.
  • Use the aria-valuetext to provide an alternative to the percentage typically spoken by assistive technologies (e.g. "32 dollars", "78 degrees")
  • For most range roles, if aria-valuemin is not defined it's default value is 0.
  • For most range roles, if aria-valuemax is not defined it's default value is 100.
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