1. DomName('DOMTokenList.add')
  2. DocsEditable()
  3. Experimental()
void add(String tokens)

Source 

@DomName('DOMTokenList.add')
@DocsEditable()
@Experimental() // untriaged
void add(String tokens) => _blink.BlinkDOMTokenList.instance.add_Callback_1_(this, tokens);