Code

function slbLoaded()
{
      var applet = <%= shapeListBox.AppletElement %>;
      applet.getShapeListBox().clearShapes();
      addShapesToList(applet, [ "Rectangle","Ellipse"]);
}

function addShapesToList(shapelistApplet, shapeIdArray)
{
      var scriptHelper = shapelistApplet.getScriptHelper();
      var slb = shapelistApplet.getShapeListBox();
      for (i = 0; i < shapeIdArray.length; ++i)
      {
            var shape = scriptHelper.shapeFromId(shapeIdArray[i]);
            slb.addShape(shape);
      }
}