function showLicense(url) {
  var scrollTop = document.body.scrollTop;

  if (scrollTop == 0) {
    if (window.pageYOffset)
      scrollTop = window.pageYOffset;
    else
      scrollTop = (document.body.parentElement) ? document.body.parentElement.scrollTop : 0;
  }

  document.getElementById('shader').style.display = 'block';
  document.getElementById('window').style.display = 'block';
  document.getElementById('window').style.top = (scrollTop + 100) + 'px';
  document.getElementById('iWindow').src = url;
}