script.js

var prevThread;

var observer = new MutationObserver(records=>{
try {
  const thread = document.getElementsByClassName('z38b6 CnDs7d hPqowe')[0];

  if (prevThread != undefined && thread.isEqualNode(prevThread)) return;
  if (thread.getElementsByClassName('gYckH').length == 1) return;
  prevThread = thread.cloneNode(true);
  const messages = thread.getElementsByClassName('oIy2qc');
  const message = messages[messages.length-1].innerText;

  var screen = document.body; // よくない
  var screenHeight = screen.offsetHeight;
  var screenWidth = screen.offsetWidth;

  var comment = document.createElement('span');

  comment.textContent = message;
  document.getElementsByTagName('body')[0].appendChild(comment);

  var letterSize = screenHeight*0.05;

  comment.setAttribute('class', 'comment');

  var commentStyle = {
    left: screenWidth + 'px',
    top: Math.floor((screenHeight - letterSize) * Math.random()) + 'px',
    fontSize: letterSize + 'px',
  }
  for(var prop in commentStyle) {
    comment.style[prop] = commentStyle[prop];
  }


  $(comment).animate(
    {
      'left': -comment.offsetWidth + 'px'
    },
    {
      'duration': 6000,
      'easing': 'linear',
      'complete': function() {
        document.getElementsByTagName('body')[0].removeChild(comment);
      }
    });
}
catch(e) {
  return;
}
});

const config = {
  attributes: true,
  subtree: true,
  childList: true,
  characterData: true
}

document.addEventListener('DOMContentLoaded', () => {
  var elem = document.body; // ほんとはチャットボックスを監視するべきだけどmeetに参加画面と判断するのめんどくさい これのせいで重い
  observer.observe(elem, config);

  var cas = document.createElement('iframe');
  cas.setAttribute('src', 'https://river.tango-gacha.com/')
  cas.setAttribute('width', '100%')
  cas.setAttribute('height', '100%')
  cas.setAttribute('frameborder', '0')
  cas.setAttribute('style', "position:absolute;border:0;width:100%;filter:invert(100%);-webkit-filter:invert(100%);z-index:2147483647;pointer-events:none;")
  var elem = document.body;
  elem.appendChild(cas)
});