ARIA is a tool for enhancing web accessibility, which is used to supplement HTML semantics deficiency and help assistive technologies understand complex components. It defines element roles through roles, such as navigation or dialog boxes; uses aria-label and aria-describedby to provide tags and descriptions; uses aria-expanded and aria-selected to reflect the status; and uses aria-live to notify dynamic content updates. When using it, native tags should be given priority to avoid redundancy, dynamically update properties and test them. Examples include using aria-haspopup and role="menu" in the drop-down menu, form error prompt association, and dynamic search suggestions to set aria-live.

The ARIA (Accessible Rich Internet Applications) attribute is an important tool for enhancing web accessibility, especially in HTML5, which can help assistive technologies such as screen readers to better understand page content and interactive functions. If you want your website to be friendly to all users, especially for people with disabilities, it is very important to use ARIA attributes properly.

What is ARIA and why do you need it?

HTML itself already has certain semantic capabilities, such as <button></button> , <nav></nav> , and <header></header> tags themselves have clear meanings. However, in some complex UI components, such as custom drop-down menus, modal boxes, dynamically loaded content areas, etc., HTML tags alone cannot accurately express their purpose and status. At this time, ARIA needs to "additional explanation".

ARIA tells the auxiliary technology the role, status, role and other information of the current elements by adding additional attributes. For example, a button simulated by <div> can be used to tell the screen reader that this is a button through <code>role="button" , and then it is pressed with aria-pressed="true" .

Common ARIA properties and usage suggestions

Here are some commonly used ARIA properties and their applicable scenarios:

• role : defines the type or purpose of an element, such as role="navigation" and role="dialog" .
• aria-label / aria-labelledby : Provides readable labels for controls without visible text, such as icon buttons.
• aria-describedby : used to associate descriptive text, suitable for interpreting form fields format requirements.
• aria-expanded : is often used to collapse panels or drop-down menus to indicate whether it is currently expanded.
• aria-selected / aria-checked : Applicable to status prompts for interactive elements such as tabs and check boxes.
• aria-live : Content areas used for dynamic updates, such as notification bars, search suggestions, etc., so that screen readers can report changes in a timely manner.

Recommended usage:

• Try to give priority to using native HTML semantic tags, and use ARIA only if necessary.
• Don't abuse role , such as don't add role="button" to <button></button> , this is unnecessary.
• ARIA attributes need to be updated dynamically according to state changes, such as switching the aria-pressed value after clicking.
• Testing is important, it is best to use a screen reader to test the actual effect, such as NVDA, JAWS, or VoiceOver.

How to apply ARIA in common components

Dropdown menu (Dropdown)

A typical example is a JavaScript control displaying hidden menu button:

 <button aria-haspopup="true" aria-expanded="false" id="menu-button">Menu</button>
<ul role="menu" aria-labelledby="menu-button" hidden>
  <li role="menuitem"><a href="#">Option 1</a></li>
  <li role="menuitem"><a href="#">Option 2</a></li>
</ul>

In this structure, aria-haspopup indicates that the button will pop up the menu, aria-expanded reflects whether it is currently expanded, while role="menu" and role="menuitem" help the screen reader to identify the menu structure.

Form verification tips

When the form input is incorrect, you can use aria-describedby to point to the error message:

 <input type="text" id="email" aria-describedby="email-error">
<div id="email-error" class="error" hidden>Please enter a valid email address</div>

This way the screen reader will automatically read the error message when the user focuses on the input box.

Dynamic content updates (such as search suggestions)

If there is an autocomplete search box, you can set aria-live="polite" to let the assistive technology know that the content here will change:

 <div id="suggestions" aria-live="polite"></div>

This way, when the suggestion list appears, the screen reads out aloud, but does not interrupt the user's current operation.

Basically that's it. ARIA is not a must, but it is a key part of improving the accessibility experience when building modern web applications, especially when using a lot of JavaScript dynamic rendering. Using it correctly can make your website more inclusive and professional.