gridThickness: Number

Sets the Thickness of Grid Lines. To display grid on Axis X, set the Grid Thickness to a number greater than zero.

• You can hide Grid Lines by setting the value to Zero

var  chart =  new  CanvasJS.Chart("container",
{
 .
 .
 axisY:{
   gridThickness: 5,
 },
 .
 .
});
chart.render();