Which methods are acceptable for adding alternative text to <canvas> elements?

Using aria-label to provide alternative text for elements is a suitable method because it allows screen readers to understand and convey the purpose of the canvas content to visually impaired users. Unlike standard HTML elements, the element does not support an alt attribute, making traditional methods of adding alternative text inadequate. By using aria-label, you directly associate descriptive text with the canvas, ensuring that users who rely on assistive technologies have the context needed to understand the content or function of the canvas.

Referring to text via aria-labelledby can also be an effective way to provide accessible context by linking the canvas to another element whose text serves as a label. However, the aria-label method is a more straightforward approach when you want to render a concise description directly associated with the canvas and does not depend on the presence of an additional element.

Providing text within the element itself will generally not be accessible since content rendered inside the canvas becomes graphical, and is not exposed to screen readers in a meaningful way. Text in the alt attribute cannot be used with as it is not a recognized approach for this element. Therefore, using aria-label stands out as the best choice for adding alternative text to ensure accessibility.