Is there an online emulator of a screen tool to validate on a custom web page?

Not. At least not one that is good, and does not show how the screen scanner actually reads the page or responds to ARIA.

The best answer is to test with real screen readers, ideally by getting real users as they know how to use these tools. Consider contacting your local association for the blind and see if they offer testing services.

Screen readers

Each platform has a screen reader, most of which are built in. Windows has the greatest variety.

For Windows

• Use a storyteller (it's built in, although not very good, it gets much better now). Use it with Edge.

• Download the free NVDA screen reader (but please donate to support it). Use it with Firefox

• Download JAWS and use it in 40 minute steps for free. Use it with IE11.

For macOS

• Use VoiceOver (it's built in). Use it with Safari.

For iOS

• Use VoiceOver (it's built in). Use it with Safari.

For Android

• Use TalkBack . Use it with Firefox.

For Ubuntu

• Use Orca .

For ChromeOS

• Use ChromeVox (but this mode can only be used in ChromeVox, not as a Chrome plugin on Windows or macOS).

Resources

It is convenient to start testing yourself. Key shortcuts are required to use the screen reader correctly, except that we press the key over and over again Tab

.

• Basic screen reader commands for testing accessibility

• Screen readers and web browsers - which is best for testing?