<!DOCTYPE html> <html class="reftest-wait"> <style> button { padding: 0px; border:none; font-size: 64px; background-color: green; } button::-moz-focus-inner { padding-inline-start: 0px; padding-inline-end: 0px; } button:-moz-focusring::-moz-focus-inner { border: 4px solid; } </style> <div> <button id="button1"><span>Menu1</span></button> </div> <script> window.onload = () => { button1.focus(); document.documentElement.classList.remove('reftest-wait'); } </script> </html>