SimulAT Panel

The SimulAT feature of the Attest extension provides a text-based simulation of how a screen reader would read a webpage. In fact, the title "SimulAT" is a play on words, combining the word "Simulate" with the acronym "AT," which stands for Assistive Technology. Screen readers are a type of assistive technology for people with disabilities. Rather than read the page aloud as a real screen reader would, SimulAT creates a text transcript of what a screen reader would say. Note that this is an approximation based primarily on the behavior of the JAWS screen reader by Freedom Scientific. There are subtle differences between brands of screen readers such as JAWS, NVDA, VoiceOver, and WindowEyes. SimulAT does not represent all of the subtle differences between brands, but it does give a general idea of the kinds of things screen readers convey to users.


A complete accessibility evaluation requires testing with real screen readers, especially in the case of dynamic content, ARIA, and JavaScript.

SimulAT allows you to analyze the entire loaded page (web document) or select part of the page content or page structure (such as headings, tables, frames, links, etc.) to analyze. Running a SimulAT analysis serves as a tool to help you inspect the page to uncover accessibility issues.

The SimulAT panel with entire document simulation example displayed, and each primary component of the tool numbered 1-4

The SimulAT tool is made up of the following four primary components:

  1. Select topics: menu (display options): Provides a list of the following content and structure element options you can select to be included in the resulting simulated display:
    • Entire document: Get an overall big picture of how a screen reader would read the whole page (including all structure and content targets).
    • Page structure (all page structure): Include all headings, tables, frames, and iframes in the resulting display.
      • Headings: Check for good heading structure by viewing a list of headings and their levels.
      • Tables: Identify the relationships between cells and their content, verify appropriate caption, summary and header cell information.
      • Frames and iframes: Check for improper heading order, meaningless frame content that can be hidden, and missing title attributes that screen readers use to identify content and purpose.
    • Page content (all page content): Includes links, images and area tags in the resulting display.
      • Links: Verify link text is descriptive to enable screen reader users to locate them quickly.
      • Images: List images and their alt text (or file name if the alt text is missing) to identify inappropriate and missing alt text.
      • Area tags: Find missing alt attribute values for clickable areas of image maps.
    • Run again link ("re-SimulAT"): Performs the same action as the RUN SIMULAT button after clearing out the currently-displayed simulation results. Initiates the screen reader compatibility analysis (SimulAT) according to the option selected in the Select topics: section and returns results in the main Content pane at right. For detailed information, see Analyzing a Page for Screen Reader Compatibility (Running SimulAT).
    • Inspect and Highlight links ("with selected"): After an element has been selected in the Content (simulation results) pane, click these links to either Inspect or Highlight the element.
      • Inspect link: Click to view its associated source code in the Inspector developer tool. For detailed information, see Inspecting the Code of an Element from SimulAT Results.
      • Highlight link: After an element has been selected in the Content (simulation results) pane, click this link to view its associated element and visual location on the rendered page in the browser (surrounded with an outline border of dashes in a contrasting color). This remains active for subsequent element selections until stopped. For detailed information, see Highlighting an Element on a Page from SimulAT Results.
    • Content pane (results transcript): Displays the generated report output of the simulation based on your selection in the Display field in a vertically-scrollable region with selectable element tags that appear as color-coded buttons. Results simulate how screen readers and other assistive technologies will understand the structure and content of the page. For detailed information, see Analyzing a Page for Screen Reader Compatibility (Running SimulAT).