viewfinder-regular/src/public/plugins/demo/doingit.js

Remote isolated browser platform by Dosyago

function installFormSubmitButtonHandler() {
  const forms = document.querySelectorAll('form'); 
  forms.forEach(form => form.addEventListener('submit', e => {
    const button = form.querySelector('button');
    button.disabled = true;
    button.innerText = 'Doing it...';
  }, {passive:true}));
}