<!DOCTYPE html>
<title>Various test cases producing infinite active duration</title>
<link rel="help" href="https://drafts.csswg.org/css-animations-1/#animation-iteration-count" />
<script>
  let effect = new KeyframeEffect(null,
    { opacity: [0, 1] },
    { duration: 1, delay: -17592186044416, iterations: Infinity });
  effect.getComputedTiming();

  // Infinity delay + Infinity active duration
  effect = new KeyframeEffect(null,
    { opacity: [0, 1] },
    { duration: 1, delay: Number.MAX_VALUE, iterat