# JS API Reference

# Welcome to the Highcharts JS Options Reference

These pages outline the chart configuration options, and the methods and properties of Highcharts objects.

Feel free to search this API through the search bar or the navigation tree in the sidebar.

# drilldown.activeAxisLabelStyle

Additional styles to apply to the X axis label for a point that has drilldown data. By default it is underlined and blue to invite to interaction.

In styled mode, active label styles can be set with the `.highcharts-drilldown-axis-label` class.