move-up-with-hidden-elements.html | Explore in Territory

<!doctype html>
<script src="../resources/runner.js"></script>
<div id="sample"></div>
<script>
const kElements = 10000;

const metaElements = (() => {
  const result = [];
  for (let count = 0; count < kElements; ++count)
    result.push('<meta>', '</meta>');
  return result;
})();
const sample = document.getElementById('sample');
sample.innerHTML =   [
  '<h1 id="before">first line of renderered text</h1>',
  '<div hidden>', ...metaElements, '</div>',
  '<h1 id="target">second line of renderered text</h1>',
  '<div hidden>', ...metaElements, '</div>',
  '<h1 id="after">third line of renderered text</h1>',
].join('');

const selection = window.getSelection();

PerfTestRunner.measureTime({
  description: 'Measures performance of move-up through non-renderered elements',
  setup: () => {
    selection.removeAllRanges();
    const target = document.getElementById('target');
    selection.collapse(target.firstChild, 5);
    selection.extend(target.firstChild, 10);
  },
  run: () => {
    selection.modify('extend', 'backward', 'line');
  },
});
</script>

chromium/third_party/blink/perf_tests/editing/move-up-with-hidden-elements.html