v148 · Performance · Container Timing
Content Visibility Meter
Six content sections use content-visibility: auto. A Container Timing observer measures when each becomes visible. Toggle content-visibility on/off and watch the timing entries change.
API probe:
PerformanceObserver for container entries (Container Timing)Checking…
Container Timing — section paint times
Summary
Fastest section—
Slowest section—
Time to fully interactive—
content-visibility modeauto
API modechecking
ignored subtrees0
Page sections with containertiming attribute
Lazy Section Loader
Inject content progressively — watch Container Timing capture each paint
No sections injected yet.
PerformanceObserver Log
--:--:--PerformanceObserver watching for "container" entries (Container Timing)…
how it works
// Mark sections
<section containertiming="hero">…</section>
// Observe
const po = new PerformanceObserver(list => {
list.getEntries().forEach(entry => {
console.log(entry.identifier, entry.startTime);
});
});
po.observe({ type: 'container', buffered: true });