[Solved]-Highcharts' verifying stacking issues-Highcharts

You need to define what series you want to know the stacking for.

var stackedVal;
stackedVal = chart.series[0].options.stacking;
alert(stackedVal);

The reason you can't get the global stacking value is because it is on override from the individual series elements. So you could set the plotOptions.series.stacking = 'normal' but in each of the series you can set its own individual stacking. It is always better to read from what a particular series is actually doing.

DEMO

The problem is that you said you did the following:

chart.options.plotOptions.series.stacking = 'normal';
                            ^

But you did it ?
No, if you take a look your fiddle, you'll see that you did the following:

chart.options.plotOptions.column.stacking = 'normal';
                            ^

That's why you're getting undefined

demo