// Mouseover event to remove scrolling from parent window's document.
document.body.addEventListener('mouseover', function() {
    parent.window.document.html.style.overflow = 'hidden';
  });
  // Mouseover event to restore scrolling on parent window's document.
  document.body.addEventListener('mouseleave', function() {
    parent.window.document.html.style.overflow = '';
  });