This information is directly accessible from a Axis
object. For example:
var chart = $('#container').highcharts();
var axisMax = chart.yAxis[0].max; // Max of the axis
var dataMax = chart.yAxis[0].dataMax; // Max of the data
As mentioned you can use Axis.getExtremes
(API) , but the same data is also available as:
Axis.min
: Min of the axis
Axis.max
: Max of the axis
Axis.dataMin
: Min of the data
Axis.dataMax
: Max of the data
And even some historic data if the extremes of the axis has changed:
Axis.oldMin
: The previous min of the axis
Axis.oldMax
: The previous max of the axis