The Navigator date picker allows changing the selected date range using the select() client-side method:

javascript html5 date picker select method

It uses the current selection mode  (Day, Week, Month) and selects the time range accordingly. The date parameter can be any of the dates belonging to the time range (it doesn't have to be the first one).

Examples:

<div id="nav"></div>

<script>

  const nav = new DayPilot.Navigator("nav", {
    // ...
    selectMode: "Week"
  });

  nav.init();

  // ...

  nav.select("2022-03-08");

</script>