code: function (event) {
  		var chart = this,
  			hasZoomed,
  			pointer = chart.pointer,
  			displayButton = false,
  			resetZoomButton;
  
  		// If zoom is called with no arguments, reset the axes
  		if (!event || event.resetSelection) {
  			each(chart.axes, function (axis) {
  				hasZoomed = axis.zoom();
  			});
  		} else { // else, zoom in on all axes
  			each(event.xAxis.concat(event.yAxis), function (axisData) {
  				var axis = axisData.axis,
  					isXAxis = axis.isXAxis;
  
  				// don't zoom more than minRange
  				if (pointer[isXAxis ? 'zoomX' : 'zoomY'] || pointer[isXAxis ? 'pinchX' : 'pinchY']) {
  					hasZoomed = axis.zoom(axisData.min, axisData.max);
  					if (axis.displayBtn) {
  						displayButton = true;
  					}
  				}
  			});
  		}
  		
  		// Show or hide the Reset zoom button
  		resetZoomButton = chart.resetZoomButton;
  		if (displayButton && !resetZoomButton) {
  			chart.showResetZoom();
  		} else if (!displayButton && isObject(resetZoomButton)) {
  			chart.resetZoomButton = resetZoomButton.destroy();
  		}
  		
  
  		// Redraw
  		if (hasZoomed) {
  			chart.redraw(
  				pick(chart.options.chart.animation, event && event.animation, chart.pointCount < 100) // animation
  			);
  		}
  	}
docs: Zoom into a given portion of the chart given by axis coordinates
  @param {Object} event