<!doctype html>
<div id=target></div>
<script>
// This is a regression test for crbug.com/1063652, the test pass as long as it
// doesn't crash.
CSS.registerProperty({
  name: '--c',
  syntax: '<number> | initial-value',
  initialValue: 'initial-value',
  inherits: false,
});
let animation = target.animate({
  '--c': [, '300' ],
}, {
  duration: 1,
});
if (window.testRunner)
  testRunner.dumpAsText();
</script>