n map initialization)
				}
				else if (tr != null) 
				{
					map.panBy([(oldTr.x - tr.x) * s, (oldTr.y - tr.y) * s]);
				}
			}; 
			
			graph.view.addListener(mxEvent.SCALE_AND_TRANSLATE, zoomPanListener);
			graph.view.addListener(mxEvent.TRANSLATE, zoomPanListener);
			graph.view.addListener(mxEvent.SCALE, zoomPanListener);

			document.getElementById('zoomIn').addEventListener("click", function(){
				graph.zoomIn();
			});
			
			document.getElementById('zoomOut').addEventListener("click", functio