get class names from dom

by John Allan

HTML

<div class="aclass bclass">
<div class="cclass bclass">
<div class="aclass xclass dclass">
<div class="aclass bclass">

</div>
</div>
</div>
</div>

JavaScript

var c = [];

document.querySelectorAll('*').forEach(function (value, index) {
	c = c.concat(value.className.split(' '));
});

c = c.sort().filter(function (value, index, arr) {
	var b =  !index || value !== arr[index - 1];
  if (b) { console.log(value); }
  return b 
});