 = originalStartNode.cloneNode(false);

    // "Set the data of clone to the result of calling substringData() on
    // original start node, with original start offset as the first
    // argument and (length of original start node − original start offset)
    // as the second."
    clone.data = originalStartNode.substringData(originalStartOffset,
      nodeLength(originalStartNode) - originalStartOffset);

    // "Append clone as the last child of frag."
    frag.appendChild(clone);
  // "Otherwise, if 