# Welcome to the Highcharts Gantt JS (gantt) Options Reference

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

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# yAxis.dateTimeLabelFormats

For a datetime axis, the scale will automatically adjust to the appropriate unit. This member gives the default string representations used for each unit. For intermediate values, different units may be used, for example the `day` unit can be used on midnight and `hour` unit be used for intermediate values on the same axis.

For an overview of the string or object configuration, see dateFormat.

Defaults to:

    {
        millisecond: '%[HMSL]',
        second: '%[HMS]',
        minute: '%[HM]',
        hour: '%[HM]',
        day: '%[eb]',
        week: '%[eb]',
        month: '%[bY]',
        year: '%Y'
    }