# Welcome to the Highcharts Gantt JS (gantt) 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.

# navigator.xAxis.tickmarkPlacement

For categorized axes only. If `on` the tick mark is placed in the center of the category, if `between` the tick mark is placed between categories. The default is `between` if the `tickInterval` is 1, else `on`. In order to render tick marks on a category axis it is necessary to provide a tickWidth.