javascript - Highchart - Changing label text of the yaxis programatically -

i have searched on net , highchart documentation, option required change label of yaxis graph (let's spline).

i have gotten close

chart.yaxis[0].options.label 

which seems valid, not figure out how use it.

also, if have multiple yaxis, how yaxis object id, can manipulate particular label.

note: not title text, looking label.

right statically setting -

chart.addaxis({ . . . title: { text: "my label", align: "high", y: -20, rotation: 0, }, . . });

have @ axis.update(). let modify axis. axis update can specify index (the order in added axis starting @ 0).