Fruit of the Accessibility Tree: The Journey from Browser to User, PDF of slides for the presentation

Handouts Media

Presented at 3:00pm in Virtual B on Thursday, November 19, 2020.



  • Derek Jackson, Digital Accessibility Developer, Harvard University

Session Details

  • Length of Session: 45 minutes
  • Format: Lecture
  • Expertise Level: All Levels
  • Type of session: Pre-conference


Assistive technology does not interact directly with the content displayed in our browsers, or the HTML behind the scenes. Instead it relies on a parallel structure to what we see called the “Accessibility Tree.” This structure is what the browser and assistive technology use to interact with one another. Equipped with a better understanding of the accessibility tree we are better able incorporate accessibility into our work at the onset. This presentation will take a peek under the hood of this technology to understand the process.


Many of us are working to create accessible experiences with little understanding of the process behind the technology we rely on. Some of us may have some awareness of the accessibility tree, or how a browser works, or what a screen reader does. However, how all these pieces are connected to deliver information to users of assistive technology may remain shrouded in mystery. This presentation aims to fill in those blanks with an overview of the process.

Specifically we will look at what happens to HTML, CSS and JavaScript when it reaches the browser; how a browser uses this information to build an accessibility tree; how assistive technology uses the accessibility tree to interact with the browser; and how this understanding applies to our own work in accessibility. Ultimately, understanding the accessibility tree and how the browser interacts with assistive technology helps us create and design more accessible experiences on the web. This is not an “in the weeds” look at the technology behind browsers and operating systems but an approachable overview of how information travels from the browser to the user.


  1. It is important to understand the flow of information from browser to assistive technology.
  2. Understanding the accessibility tree's key role in this process and how we impact it.
  3. Applying this knowledge to work of designers and developers can improve the accessibility of web content.

Disability Areas

All Areas

Topic Areas

Assistive Technology, Uncategorized, Web/Media Access

Speaker Bio(s)

Derek Jackson

Derek is a Digital Accessibility Developer with Digital Accessibility Services at Harvard University, where he works with a team of developers and consultants to provide a host of accessibility service to the Harvard Community. Before working in this role he was at Harvard Business School Publishing where he worked in Higher Ed as the Assistant Director of Content Publishing. While at HBP Derek worked to make delivering accessible content a priority, building accessibility into publishing work flows and also creating an accessibility roadmap for the Higher Education group. Derek graduated from Simmons University with a M.S. in Information Science and also graduated from City University New York with a M.A. in Liberal Studies.