<!DOCTYPE html> <!-- `reftest-snapshot-all` is necessary to take the screenshot for whole canvas when zoom level is changed. This is the same as what we do in the case where reftest-async-zoom is specified. --> <html class="reftest-wait reftest-snapshot-all"> <meta name="viewport" content="width=device-width, minimum-scale=0.5"> <style> html { overflow: hidden; } html, body { margin: 0; width: 100%; height: 100%; } div { position: absolute; } </style> <div id="red" style="background: red; width: 100%; height: 300%;"></div> <div id="green" style="background: green; width: 100%; height: 200%;"></div> <div style="background: blue; width: 100%; height: 100%;"></div> <script> document.addEventListener('MozReftestInvalidate', () => { green.style.width = '200%'; red.style.width = '300%'; requestAnimationFrame(() => { document.documentElement.classList.remove('reftest-wait'); }); }); </script> </html>