There's also insertBefore, which you can use to move a node anywhere:

  parentNode.appendChild(node);                         // move to top
  parentNode.insertBefore(node, parentNode.firstChild); // move to the bottom
  parentNode.insertBefore(node, someNode);              // move just below someNode
  parentNode.insertBefore(node, someNode.nextSibling);  // move just above someNode