Available since v0.1.0

fs-trigger="load"

Stable

Fires on the native load event of media elements. Use for image, video, or iframe load validation.

Syntax

<img src="/hero.webp"
  fs-assert="home/hero-loaded"
  fs-trigger="load"
  fs-assert-loaded="img.hero">

When to use it

Hero image load validation
Video or iframe loaded-successfully contracts
Anything where "did the resource actually fetch?" is a visible correctness signal

Example

<video src="/demo.mp4" controls
  fs-assert="demo/video-loaded"
  fs-trigger="load"
  fs-assert-loaded="video">
</video>

Pairs well with

fs-assert-loaded — the natural partner for this trigger
Conditional assertions — pair with error for success/failure branches

Gotchas

Cached resources. Browsers fire load synchronously for cached resources. If the image is in cache when the agent initializes, the event may fire before the assertion is registered. Prefer fs-assert-loaded which also checks .complete for the cached case.
iframe load is noisy. Every navigation inside the iframe fires another load. Scope the assertion key appropriately.

See also

error — the failure counterpart
fs-assert-loaded
Triggers index