Dynamic y2 axis update

From this link http://jsfiddle.net/7kYJu/387/

I would like to have it as dynamic as below for my requirement, Could you help?
var myData1 = 'data1';
var myData2 = 'data2';
var myData3 = 'data3';

data: {
columns:[
['data1', 30, 20, 50, 40, 60, 50, 100, 200],
['data2', 230, 220, 250, 240, 260, 250, 300, 400],
['data3', 130, 220, 350, 140, 360, 250, 100, 300]
],
labels: true,
axes: {
myData1: 'y',
myData2: 'y',
myData3: 'y2'
}
},