ui-debug.js

document.body.style.paddingBottom = '250px';
const div = document.createElement('div');
Object.assign(div.style, {
  position: 'fixed',
  bottom: 0,
  left: 0,
  right: 0,
  height: '250px',
  opacity: 0.90,
  color: 'white',
  backgroundColor: 'black',
  zIndex: 9999,
  padding: '3px',
  overflow: 'scroll',
  border: '1px solid grey',
  borderBottomWidth: 0,
  borderLeftWidth: 0,
  borderRightWidth: 0,
  fontFamily: 'monospace',
  fontSize: '10px',
  lineHeight: '10px',
});
document.body.append(div);
window.log = (arg) => {
  const log = document.createElement('div');
  log.innerHTML = `${JSON.stringify(arg, null, 2)}<br /><br />`;
  div.prepend(log);
};