Technical Implementation

PhET simulations are rendered in a custom scene graph for HTML5 called Scenery. With Scenery, interactive graphics can be displayed using Canvas and SVG. These elements are not structured to provide any information about their internal structure (the content of the simulation) to assistive devices. To address this challenge, we explored multiple approaches to providing assistive technologies with the information they utilize to provide access to users, and determined that the implementation of a Parallel DOM structure provided the most generalizable approach. You can learn more about our implementation approaches through the documentation below.

Challenges with Accessibility for PhET Sims
Parallel DOM: Structure and Implementation
Open Questions for Accessible Content in Interactive Simulations
Previous Implementations