code: function contains(parent, child) {
  		if (!parent || !child) { return false; }
  		if (parent === child) { return true; }
  		var compare = parent.compareDocumentPosition(child);  // useful to break out for debugging
  		return Boolean(compare & 16);
  	}
docs: Returns whether <code>child</code> is a descendant of <code>parent</code> in the DOM order.
  @function
  @param {Node} parent
  @param {Node} child
  @returns {Boolean}