code: function insertPart(part){
        var text = "\n";
        if (part.nodeType == 3) {
          select.snapshotChanged();
          part = makePartSpan(part, owner);
          text = part.currentText;
          afterBR = false;
        }
        else {
          if (afterBR && window.opera)
            point(makePartSpan("", owner));
          afterBR = true;
        }
        part.dirty = true;
        nodeQueue.push(part);
        point(part);
        return text;
      }
docs: Insert a normalized node at the current point. If it is a text node, wrap it in a <span>, and give that span a currentText property -- this is used to cache the nodeValue, because directly accessing nodeValue is horribly slow on some browsers. The dirty property is used by the highlighter to determine which parts of the document have to be re-highlighted.