a11y_highContrastButton: Accessible high-contrast toggle button
In a11yShiny: Accessibility Enhancements to Popular R Shiny Functions

a11y_highContrastButton

R Documentation

Accessible high-contrast toggle button

Description

A toggle button that switches high-contrast mode by adding/removing the CSS class .high-contrast on the ⁠<body>⁠ element, with ARIA attributes according to BITV 2.0.

Usage

a11y_highContrastButton(
  inputId = "toggle_contrast",
  label = "Contrast Mode",
  icon = shiny::icon("adjust"),
  aria_label = "Toggle high-contrast mode on or off",
  ...
)

Arguments

`inputId`	Button ID (default: `"toggle_contrast"`)
`label`	Visible label (optional, e.g. `"High Contrast"`)
`icon`	Optional icon, e.g. `shiny::icon("adjust")`
`aria_label`	ARIA label (required if `label` is missing/empty)
`...`	Additional arguments for `a11y_actionButton()`

Details

Uses a11y_actionButton() internally (visible label or aria-label).
Sets aria-pressed and toggles this state via JS.
Adds the class .a11y-high-contrast-toggle to which the JS is attached.

Value

HTML tag of the button component

Examples

# Default high-contrast toggle button
a11y_highContrastButton()

# Custom label in English
a11y_highContrastButton(
  label      = "High Contrast",
  aria_label = "Toggle high-contrast mode"
)

# Icon-only toggle (no visible label)
a11y_highContrastButton(
  label      = NULL,
  icon       = shiny::icon("adjust"),
  aria_label = "Toggle high-contrast mode"
)

a11yShiny documentation built on April 1, 2026, 5:07 p.m.