1. @DomName('Element.insertAdjacentElement')
  2. @DocsEditable()
  3. @Experimental()
Element insertAdjacentElement(String where, Element element)

Source 

@DomName('Element.insertAdjacentElement')
@DocsEditable()
@Experimental() // untriaged
Element insertAdjacentElement(String where, Element element) =>
    _blink.BlinkElement.instance
        .insertAdjacentElement_Callback_2_(this, where, element);