hidden: Function

var chart = new CanvasJS.Chart("container",
{
 .
 .
 axisX: {
   .
   .
   crosshair: {
     enabled: true,
     hidden: function ( e ) {
       console.log("Crosshair has been hidden");  
     }
   },
   .
   .   
 },
 .
 .
});
chart.render();