code: function isEditingHost(node) {
  	return node
  		&& isHtmlElement(node)
  		&& (node.contentEditable == "true"
  		|| (node.parentNode
  		&& node.parentNode.nodeType == Node.DOCUMENT_NODE
  		&& node.parentNode.designMode == "on"));
  }
docs: "An editing host is a node that is either an HTML element with a contenteditable attribute set to the true state, or the HTML element child of a Document whose designMode is enabled."