valueFormatString: String

Defines how values must be formatted before they appear in Crosshair Label.

var  chart =  new  CanvasJS.Chart("container",
{
 .
 .
axisX:{
    crosshair:{
        enabled: true,
        valueFormatString: "#,##0.##",
	.
	.
    }
},
 .
 . 
});
chart.render();