Shashi,
For your case, we suggest you to use separate variables for each chart instance or to keep all the chart instances in an array as shown below.
var chartsArray = [];
chartsArray.push(new CanvasJS.Chart("chartContainer1", { //Chart 1 Options }));
chartsArray.push(new CanvasJS.Chart("chartContainer2", { //Chart 2 Options }));
for(var i = 0; i < chartsArray.length; i++) {
chartsArray[i].render();
}
—
Thangaraj Raman
Team CanvasJS.