z: Number

Sets the z value of dataPoint. It is only applicable in case of Bubble chart. This value determines the size of the bubble.

var  chart =  new  CanvasJS.Chart("container",
{
 .
 .
 data: [{
  dataPoints: [
 {  x: 1, y: 5,  z: 15 },
  ],

  },
 ]
 .
 .
});
chart.render();