Over 96 percent of websites have detectable accessibility errors, according to the 2025 WebAIM Million analysis of the top one million home pages.
But there’s an important limitation in that statistic: automated tests only evaluate what appears when a page first loads. The modal dialogs, form validations, and single-page application interactions that define modern web experiences aren’t captured in traditional accessibility scans.
This creates an accessibility testing gap. Organizations may receive clean audit results while users with disabilities encounter substantial barriers during actual use. Understanding the difference between static and dynamic content, and why both require testing, is critical for creating truly accessible digital experiences.
What Makes Dynamic Content Different?
Traditional web content, also known or static content, is displayed when a page first loads. It remains unchanged until a user navigates to a different page. Dynamic content changes in response to user interactions without requiring a page reload.
Common examples of dynamic content include:
- Modal dialogs and pop-ups that overlay the main page
- Form validation messages that appear when users make errors
- Loading indicators that display while content fetches
- Single-page applications where entire sections update without page refreshes
- Autocomplete suggestions in search boxes
- Expandable accordions that show hidden content
- Live notifications that alert users to new information
Each of these examples shows something new from when the page first loaded. Traditional static testing doesn’t evaluate these states because they don’t exist until someone interacts with the page.
Real-World Examples
The inaccessibility of dynamic content plays out every day. For example, consider a student trying to register for courses through a university’s web application. The course catalog loads and passes all accessibility standards in its initial state. But when the student tries to add a class that’s already full, a modal dialog appears with an error message. If that modal isn’t properly announced to screen readers, the student may not know what happened or how to proceed.
Or, imagine an employee submitting an expense report through a company intranet. The form passes all accessibility checks in its static state. But when they forget to fill in a required field, an error message appears dynamically next to that field. Without proper ARIA attributes, a screen reader user might never know which field caused the error or how to correct it.
When accessibility testing only evaluates the initial page state, organizations miss the majority of barriers users encounter during real-world use.
Why Traditional Testing Falls Short
Static website scanners analyze the HTML, CSS, and other code that exists when a page first loads. They excel at identifying issues like missing alt text, insufficient color contrast, or improper heading hierarchy in that initial state.
However, these tools can’t interact with websites the way users do. For example, they can’t evaluate whether a dynamically loaded error message is properly announced, whether keyboard focus moves correctly when a modal opens, or whether single-page application route changes are communicated to assistive technologies.
Building Comprehensive Accessibility Testing
Addressing dynamic content accessibility requires evaluating how web applications behave as users interact with them. Organizations should identify critical workflows, such as course registration, checkout processes, or account management tasks, and test whether those workflows remain accessible as content changes, forms validate, and new elements appear on screen.
Effective testing captures each unique state that appears during user journeys. Specialized testing tools can help by recording workflows and evaluating accessibility throughout the user journey.
The goal is always to ensure that accessibility compliance extends to every interaction users encounter. Begin with your most critical user workflows and thoroughly test them for accessibility at each interaction point.
As you expand testing to additional paths, you’ll build a more complete picture of how users with disabilities experience your digital properties and where improvements are needed.
