Non-temporal media
Non-temporal media is multimedia content that users consume at their own pace, without an imposed chronological flow: interactive map, clickable chart, user-controlled slideshow. In accessibility, each non-temporal media must offer an accessible alternative and an adjacent, clearly identifiable link to it.
An SVG map where you click on each region to display its data. A <canvas> chart you hover over to read figures. An educational module where you choose which content to explore. Three pieces of content, one thing in common: none depend on a timeline.
#What separates non-temporal media from temporal media
The distinction comes down to a single question: does the content impose a chronological flow?
A video, a podcast, an MP3 file play out. The user experiences the pace. These are temporal media.
An interactive chart, a clickable infographic, or a user-controlled slideshow impose nothing. The user explores freely. That's non-temporal media.
A detail few people know: non-temporal media can embed temporal media. An interactive module that lets you listen to audio clips is still classified as non-temporal. It's the overall interaction model that matters, not the elements it contains.
Historically, these were Flash, Java, or Silverlight objects. Today, they're native HTML5 elements: <svg>, <canvas>, or JavaScript applications embedded via <iframe>.
#The mistake that blocks audits
Many teams integrate a <canvas> chart or interactive SVG without any alternative. A screen reader encounters a silent element.
The RGAA (criteria 4.7 and 4.8) requires two things:
- An accessible alternative: a text version, a data table, or any equivalent representation.
- A clearly identifiable link, adjacent to the media, leading to this alternative.
The trap: an aria-label on the <canvas> isn't enough. It describes the media, but doesn't replace its content. For a sales-by-country chart, the alternative must contain the same data, not just "Sales chart".
<figure>
<canvas id="sales-by-country" aria-label="Sales distribution by country">
<p>Your browser does not support this element.</p>
</canvas>
<figcaption>
<a href="/sales-data">View data in HTML table</a>
</figcaption>
</figure>The aria-label attribute identifies the media for assistive technologies. The link in <figcaption> provides access to the complete alternative. Both are necessary.
#In summary
Non-temporal media is any multimedia content without an imposed chronological flow. Interactive map, <canvas> chart, user-controlled slideshow: each case requires an accessible alternative and a visible path to it. Don't confuse it with temporal media: if the content plays over time, the rules on captions and audio description apply.