.Class

.Class( classes Array|String, remove Boolean )

Adds/Removes classes to/from an Element

Remove

var Elem='.this.is.an.Elem'.Class('an',1); // remove the 'an' class;

O.ready.then(b=>b.append(Elem));

<div class="this is Elem"></div>

Add

Elem.Class(['brand','new']);

<div class="this is Elem brand new"></div>