code: function scrollIntoView(element, spot) {
    // Assuming offsetParent is available (it's not available when viewer is in
    // hidden iframe or object). We have to scroll: if the offsetParent is not set
    // producing the error. See also animationStartedClosure.
    var parent = element.offsetParent;
    var offsetY = element.offsetTop + element.clientTop;
    var offsetX = element.offsetLeft + element.clientLeft;
    if (!parent) {
      console.error('offsetParent is not set -- cannot scroll');
      return;
    }
    while (parent.clientHeight === parent.scrollHeight) {
      if (parent.dataset._scaleY) {
        offsetY /= parent.dataset._scaleY;
        offsetX /= parent.dataset._scaleX;
      }
      offsetY += parent.offsetTop;
      offsetX += parent.offsetLeft;
      parent = parent.offsetParent;
      if (!parent) {
        return; // no need to scroll
      }
    }
    if (spot) {
      if (spot.top !== undefined) {
        offsetY += spot.top;
      }
      if (spot.left !== undefined) {
        offsetX += spot.left;
        parent.scrollLeft = offsetX;
      }
    }
    parent.scrollTop = offsetY;
  }
docs: Scrolls specified element into view of its parent.
  element {Object} The element to be visible.
  spot {Object} An object with optional top and left properties,
  specifying the offset from the top left edge.