(CSS) user-modify. Редактирование по нажатию на кнопку

document.querySelector('button').onclick = function() { 
  document.querySelector('.editor').classList.toggle('active') 
}

.editor.active span { 
  display: block; 
  padding: 3px; 
  border: 1px dotted; 
 -webkit-user-modify: read-write; 
 -moz-user-modify: read-write; 
  user-modify: read-write; 
}

<button>Toggle modifying</button> 
<br><br> 
<div class=editor> 
  <span>asdasd</span> 
  <span>asdasd</span> 
  <span>asdasd</span> 
  <span>asdasd</span> 
  <span>asdasd</span> 
  <span>asdasd</span> 
  <span>asdasd</span> 
  <span>asdasd</span> 
</div>