​

<select id="mltpl" class="mdb-select md-form colorful-select dropdown-primary" multiple searchable="Search here..">

  <option value="" disabled selected>Choose your country</option>

  <option value="1">USA</option>

  <option value="2">Germany</option>

  <option value="3">France</option>

  <option value="4">Poland</option>

  <option value="5">Japan</option>

</select>

<button class="btn-save btn btn-primary btn-sm">Save</button>

​

$(() => {

  $('#mltpl').materialSelect();

  $('#mltpl').val(["2", "3", "4"]);

});

​