Syynth

(() => {
  const container = document.createElement('div');
  container.innerHTML = 
  `<div>Volume</div>
  <input type="range" value="1" min="0" step="0.01" max="1">`;
  
  document.querySelector('#playcontrols_container').after(container);
  
  const audio = document.querySelector('#audioplayer');
  const volume = container.querySelector('input[type="range"]');