How to automatically substitute allowfullscreen="allowfullscreen" in a YouTube video?

Question

YouTube

Such a problem through the opencart admin panel, when uploading a product, videos are inserted initially without allowfullscreen="allowfullscreen",
Because of this, it is not possible to switch to full-screen video mode. Manually edit this crap every time. How can the problem be solved? Can the script somehow substitute the machine? Maybe someone has such a script or another solution...

Answer 1

window.onload = function() {
  //elem думаю найдете сами с помощью querySelector() / getElementBy...
  elem.setAttribute('allowfullscreen', 'allowfullscreen')
}

Answer 2

Place the code on the page:

<script type="text/javascript">

// Дожидаемся готовности стр. и выполняем код в функции:
document.addEventListener('DOMContentLoaded', function() {

  // Ищем все youtube-фреймы на странице:
  all_iframe = document.querySelectorAll('iframe[src*="youtube"]');
  
  // Обходим все найденные фреймы в цикле и присваиваем атрибут:
  for (i = 0; i < all_iframe.length; i++) {
    all_iframe[i].setAttribute('allowfullscreen', 'allowfullscreen');
  }
  
});

</script>