Flashing limits

Definition A page must not include content that flashes more than three times in one second, unless below general flash and red flash thresholds.
Purpose
  • People who have photosensitive seizure disorders can have a seizure triggered by content that flashes at certain frequencies for more than a few flashes.
  • People are even more sensitive to red flashing than to other colors.
  • NOTE: This flashing requirements was adapted from the broadcasting industry standards (e.g. content is viewed from a closer distance and using a larger angle of vision).
Required Yes for HTML4 Legacy Techniques ruleset mapping
WCAG 2.0 Success Criteria

2.3.1 Three Flashes or Below Threshold (Level A, Primary Success Criterion)

Rule Category Timing
Scope Element
Target Resources Canvas, SVG and image animations; flashing text content; video; and embedded applications
  • applet
  • embed
  • img
  • object
Techniques
  • There is no remedication technique, the content must be removed or disabled from flashing.
Informational Links