Similar to a toggle button or checkbox, a switch control is meant to be used when its visual appearance most resembles an "on and off" "switch".
The expected user experience of a switch control is for an immediate action to take place. For instance, toggling a light/dark theme for a website or application, where the change should instantly take effect.
A checkbox, which is often found within a form, or in other UI where multiple elements can be checked, may not be understood to enact an immediate change to other elements or content in the document/screen. That's not to say additional information couldn't be presented to the user to indicate such functionality for a checkbox, but it's not a standard expectation.
A toggle button and switch are a bit more similar in that they both have an expectation for an immediate change from user interaction. Their primary differences revolve around the manner in which they are supposed to communicate state to assistive technology users, as well as the visual design they each may be most associated with.
A toggle button is typically announced as "pressed" or "selected" in its active state, where a switch should be announced as "on".
The baseline for this component requires one of the following markup patterns:
<button type="button" data-switch class="class_here" disabled>
<!-- Meaningful label here -->
</button><label class="class_here">
<input type="checkbox" data-switch>
<!-- Meaningful label here -->
</label>For instance, such as a <div> or <span>.
<span class="class_here" data-switch hidden>
<!-- Meaningful label here -->
</span>data-switch is required for each markup pattern to be successfully transformed into a role="switch". All setup and functionality is based around this attribute. The attribute can be set without a value, to default a switch to the "off" state. Setting the value to "on", e.g., data-switch="on will default the switch to the "on" state. Note: if using a checkbox as the base markup element, and the checked attribute will also set the switch to be "on" by default, even if data-switch has no value.
You may notice that examples which do not have a checkbox base element have a default disabled or hidden attribute. This is due to the fact that these versions of the switch will not function without JavaScript. Rather than rendering a partially created that doesn't function, they can instead be disabled (for a <button>) or hidden for elements which would not expose or allow the disabled attribute.
If for some reason a switch should be disabled on initial load, use the data-keep-disabled to stop the script from removing the disabled (aria-disabled) or hidden attributes.
The JavaScript will add a role="switch" to the element with data-switch.
If the switch is not built from a base checkbox, an aria-checked attribute will be added to communicate the current state of the switch. If the base element is a checkbox, then the native checked attribute and the dirty checked state of the element will be used instead. It is not necessary, nor valid, to use an aria-checked attribute on a native checkbox or radio button.
Rather than updating this information in multiple places, please review the breakdown of screen reader issues with role="switch". While this particular link goes to an example of using role=switch on a checkbox, the same issues occur if using role=switch on a <button> element as well.
Note: With the release of iOS 12.2 (March 2019) the announcement of state has been fixed. VoiceOver will still announce role="switch" as checkboxes, but at least the checked/unchecked states are correctly exposed.
This script was written by Scott O'Hara.
It has an MIT license.
Do with it what you will :)