How to add a line at the below of xAxis in Highcharts?

Question

I want to add a line at the below of xAxis in Highcharts. I can't find any options for this issue. Could you please let me know how to add the line?

Answer 1

Unfortunately, there is no option in the API to set a bottom line for the axis, but you can use the chart.events.render() callback function to duplicate the default line.

Demo: https://jsfiddle.net/BlackLabel/z9jd8p5h/
API: https://api.highcharts.com/highcharts/chart.events.render