Resources about building accessible websites

The web is filled with dynamic and complex websites, applications, and user interfaces built using a combination of HTML, CSS, and JavaScript. However, when designed and built without accessibility in mind, these complex websites are difficult to use by people who rely on assistive technologies to browse the web.

Building websites that are accessible to people with disabilities requires semantic information about the user interface. Accessible websites allow assistive technologies, like screen readers, to convey the necessary information to help people with a range of abilities use the website.

Visit HTML5Accessibility for information on which new HTML5 features are accessibly supported by Microsoft Edge.

How accessibility works

Assistive technologies add capabilities that computers don't usually have. For example, a user who has low vision might use their keyboard in combination with assistive technology such as a screen reader, rather than directly using the browser with the mouse and screen.

For applications on Microsoft platforms and on the web, the assistive technology interacts with any combination of:

  • Microsoft UI Automation.
  • An application-specific object model such as the Document Object Model (DOM) in Microsoft Edge.

For web developers, certain HTML elements are mapped to UI Automation objects, so in selecting those HTML elements, the developer can use the accessibility properties and events built in to those elements. While developing your website, you usually only need to make sure that the API is correctly written to, or that the appropriate element is specified, for the application to be accessible.

Check out ARIA and UI automation in Microsoft Edge for more information. Accessible Universal Windows Platform (UWP) apps are explained at Accessibility in Windows Dev Center.

Many common accessibility issues with dynamic content can be addressed by good coding practice. The WCAG 2.0 documentation includes many techniques and best practices to help you create more accessible dynamic web applications. Even when coded properly, however, dynamic content isn't necessarily accessible. Accessible Rich Internet Applications (ARIA) helps overcome this issue.

For more information on web accessibility, check out the Introduction to Web Accessibility by the Web Accessibility Initiative (WAI).


The Accessible Rich Internet Applications (ARIA) specification by the W3C's Web Accessibility Initiative defines as a syntax for making dynamic web content and custom user interfaces accessible to all people. ARIA extends HTML by using additional attributes (roles, properties, and states) that are designed to convey custom semantics. These attributes are used by browsers to pass along the controls' state and role to the accessibility API.

Roles, properties, and states

ARIA roles are set on elements using the role attribute to give assistive technologies and accessibility APIs information about the element. For example, the below <li> element is assigned role="menuitem" to signify that it's an item in a menu.

<li role="menuitem">Home</li>

ARIA states and properties are aria-prefixed attributes that provide specific information about an object to help form the definition of the nature of roles. Properties are attributes that are essential to the nature of an object, like aria-readonly and aria-haspopup. Changing a property affects the meaning of the object.

In the example below, the property aria-haspopup="true" is set on a <li> menu item to signify that it has a popup:

<li role="menuitem" aria-haspopup="true">Open</li>

States don't change the nature of the object, but represent information that's associated with the object, or user interaction with the object, like aria-hidden or aria-checked. For example, the state aria-checked="false" in the example below represents that the checkbox is cleared, rather than selected:

<div role="checkbox" aria-checked="false">Accept</div>

To see a full list of roles, properties, and states, go to The Roles Model at W3C.

Assistive technology compatibility testing

Verifying that the website you are building works with real assistive technologies is the best way to ensure that you provide a good experience for users with disabilities. Since many assistive technologies make use of the keyboard, testing the keyboard accessibility of your website is a good place to start.

Keyboard compatibility testing validates that users have access to all interactive controls without requiring a mouse. Microsoft Accessibility Insights for Web is a browser extension for Microsoft Edge and Chrome that guides you and reveals several common issues.

Once you are confident that your website works well with a keyboard, try it with other assistive technologies, such as screen readers. This testing can uncover issues in the following:

  • Your HTML, ARIA, and CSS.
  • The level of support of an assistive technology for a feature or technique.

Different browsers might map elements to the platform accessibility APIs differently than Microsoft Edge maps them. While building your interface, it's important to consider each difference.

WebAIM conducts surveys with screen reader and low vision users that help you decide which assistive technologies and browsers to test.

Learning how to test

Assistive technologies are sophisticated tools. Don't assume that you're able to immediately start testing with an assistive technology without first learning about how it works. Learning to test with a screen reader has an especially steep learning curve. A novice user of screen readers might think that a screen reader has a bug, while the issue might actually be an error in using the screen reader.

Testing with Screen Readers at WebAIM provides more information about learning to test with assistive technologies.

Testing locally

Most devices include assistive technology that is built-in to the OS. Microsoft Windows includes the Windows Narrator screen reader and Windows Magnifier. 3rd party assistive technologies like NVDA, FreedomscientificSoftwareJaws, and ZoomText are available to download. Apple macOS includes the VoiceOver screen reader. And iOS, Android, and Linux all support a variety of assistive technologies.

Testing in virtual machines and emulators

Under macOS, if you want to test with an assistive technology only available for Windows, like Windows Narrator or NVDA, create a Windows virtual machine.

Android Studio includes an emulator that for you to test assistive technologies in the Android Accessibility Suite. Follow the instructions to set up a virtual device and start the emulator, then install Android Accessibility Suite from the GooglePlay store.


The iOS Simulator doesn't currently include VoiceOver.

Cloud-based testing tools

If an assistive technology isn't available on your OS or you not possible to install one on a virtual machine or emulator, cloud-based assistive technology testing tools are the next best thing.

  • Assistiv Labs (a commercial product) enables you to manually test with assistive technologies through any modern web browser. Select an assistive technology and browser and it connects you with a virtual machine, emulator, or real device that you can interact with.

See also Cloud-based emulators and simulators.

Resources for accessibility basics

These are projects and initiatives for accessibility.

The A11Y project

The A11Y Project is a community-driven effort to make web accessibility easier. Check out The A11Y Project site to learn about basic accessibility principles, their accessible pattern and widget library, and their resources on accessibility software, blogs, books, and tools.

Web Accessibility Initiative (WAI)

The W3C Web Accessibility Initiative (WAI) is an effort to help improve the accessibility of the web. Their site provides a variety of resources for Getting Started with Web Accessibility, Designing for Inclusion, tutorials and presentations, and more.

Accessibility blogs

These are blogs about accessibility.


TPGi, LLC provides consulting and technology solutions to organizations around the world to ensure that their clients reach all audiences effectively and efficiently, while meeting governmental and international standards. Their blog covers topics like web accessibility best practices, accessibility tools, and accessibility trends.

Level Access

Level Access is a digital accessibility firm supporting their clients in developing and deploying accessible products and services. Their blog addresses topics like ARIA best practices, accessibility trends, webinars, and more.

Accessible examples

These are libraries and examples for accessibility.

ally.js - Tutorials

JavaScript library to help modern web applications with accessibility concerns by making accessibility simpler. For more information, go to ally.js - Tutorials.

OpenAjax examples

The OpenAjax Alliance website is an excellent resource for verifying the rules for WAI-ARIA and provides a number of examples of WAI-ARIA implementations.


The A11Y Project offers a library of accessible widgets and patterns like menus, buttons, tooltips, and more. For more information, go to Patterns.

Accessibility techniques and tools

These are techniques and tools for improving accessibility.

Accessibility: Creating accessible extension icons for Microsoft Edge

Get guidance on creating accessible extensions icons for Microsoft Edge. For more information, go to Accessibility: Creating accessible extension icons for Microsoft Edge.

Accessible Name and Description: Computation and Mappings 1.1

This W3C mapping document explains how browsers determine name and descriptions of accessible objects from web content languages and expose them in accessibility APIs. For more information, go to Accessible Name and Description: Computation and Mappings 1.1.

Accessibility Evaluation Resources

Accessibility Evaluation Resources is a multi-page resource by the W3C that outlines different approaches for evaluating websites for accessibility. For more information, go to Accessibility Evaluation Resources.

Assistive technology compatibility tests

Test results showing how different content types and standards behave in assistive technologies (AT) like screen readers. For more information, go to Assistive technology compatibility tests.

Building accessible websites just got a lot easier

This .NET Web Development and Tools blog post describes the Visual Studio extension Web Accessibility Checker. For more information, go to Building accessible websites just got a lot easier.

Core Accessibility API Mappings 1.1

This W3C mapping document explains how the semantics of web content languages are exposed to accessibility APIs. For more information, go to Core Accessibility API Mappings 1.1.

Easy Checks – A First Review of Web Accessibility

A series of quick checks by the WAI that help you assess the accessibility of a web page. For more information, go to Easy Checks – A First Review of Web Accessibility.

How to Meet WCAG 2.0

A quick reference to Web Content Accessibility Guidelines (WCAG) 2.0 requirements (success criteria) and techniques. For more information, go to How to Meet WCAG 2.0.

HTML Accessibility API Mappings 1.0

This W3C mappings document explains how HTML5.1 element and attributes map to platform accessibility APIs. For more information, go to HTML Accessibility API Mappings 1.0.

Quick Tips

A list of quick web development tips for accessibility by The A11Y Project. For more information, go to Quick Tips.

Site Scan

The Site Scan tool on Microsoft Edge Dev Center checks for out-of-date libraries, layout issues, and accessibility issues. For more information, go to Site Scan.

Techniques for WCAG 2.0

Techniques from the W3C that provide guidance for web developers on meeting Web Content Accessibility Guidelines (WCAG) 2.0 success criteria. For more information, go to Techniques for WCAG 2.0.

Tips on Developing for Web Accessibility

Tips from the W3C on developing web content that is more accessible to people with disabilities. For more information, go to Tips on Developing for Web Accessibility.

WAI-ARIA Authoring Practices 1.1

A document by the W3C that provides readers with an understanding of how to use WAI-ARIA 1.1 and recommends approaches to make widgets, navigation, and behaviors accessible using WAI-ARIA roles, states, and properties. For more information, go to WAI-ARIA Authoring Practices 1.1.

WAI Guidelines and Techniques

A series of web accessibility guidelines and standards developed by the WAI. For more information, go to WAI Guidelines and Techniques.

Web Accessibility Evaluation Tools List

A list of web accessibility evaluation tools to help determine if websites meet accessibility guidelines. For more information, go to Web Accessibility Evaluation Tools List.

Web Accessibility Perspectives: Explore the Impact and Benefits for Everyone

A series of short situational videos by the W3C about the impact of accessibility and the benefits for everyone. For more information, go to Web Accessibility Perspectives: Explore the Impact and Benefits for Everyone.