Accessibility: What is the difference between aria-labeledby, aria-label and aria-describedby?

Before you start

The first rule of WAI-ARIA is: Not to use WAI-ARIA. The best, more maintainable and future proof experience is provided by using standard HTML elements.

Using WAI-ARIA should be reserved for custom components, where there is no native option. There is good list of examples in the w3c site, with explanations of how to use

Now, the difference

They differ on the type of information they will hold.

It can be primary or auxiliary information.

The primary information is basically the name of the element. It ismain information of an element, for example the label of an input field.

The auxiliary information, refers to extra information that is necessary to explain further. An example of this would be the validation error of an input field.

Primary information is read first, auxiliary information is read as the last piece of information of the input control. Meaning after its name and role.

Now that you understand this:

Aria-Label

The aria-label property enables you to name an element with a string that is not visually rendered.
It is used for primary information

Example:

<button type="button" aria-label="Close">X</button>

Aria-Labeledby

The aria-labelledby property enables you to reference other elements on the page to define an accessible name.

It is used for primary information

Example:

if you have a "read more link" that is embedded in a text.

<p id="bees">Bees are disappearing rapidly. Here are seven things you can do to help.<a id="bees-read-more" aria-labelledby="bees bees-read-more">Read more...</a></p>

Aria-Describedby

The aria-describedby property enables you to give further instructions to the screen reader user of how to use an element, how to fill it, or what to fix if there is an error.

It is used for auxiliary information

Example:

The validation errors of an input field are `aria-describedby`

<label for="username">Username</label><input id="username" name="username" aria-describedby="username-error">

<p id="username-error">Fill your username to continue</p>

Note that in this example, the name is the content of the label. That is the primary information.

There the screen reader will say:

"Username, input text, fill your username to continue"

Native types of descriptions are: `captions` that are used for images or tables.