@nikunj,
You can use get() to fetch the minimum and maximum values of the axisY as shown in the code snippet below –
var max = chart.axisY[0].get("maximum");
document.getElementById("displayMaximum").innerHTML = max;
var min = chart.axisY[0].get("minimum");
document.getElementById("displayMinimum").innerHTML = min;
Also, please take a look at this JSFiddle for complete working code.
___________
Indranil Deo
Team CanvasJS