How to set selected value of jQuery Select2

Question

This belong to codes prior to Select2 version 4

I have a simple code of select2 that get data from AJAX.

$("#programid").select2({
  placeholder: "Select a Program",
  allowClear: true,
  minimumInputLength: 3,
  ajax: {
    url: "ajax.php",
    dataType: 'json',
    quietMillis: 200,
    data: function (term, page) {
      return {
        term: term, //search term
        flag: 'selectprogram',
        page: page // page number
      };
    },
    results: function (data) {
      return {results: data};
    }
  },
  dropdownCssClass: "bigdrop",
  escapeMarkup: function (m) { return m; }
});

This code is working, however, I need to set a value on it as if in edit mode. When user select a value first time, it will be saved and when he needs to edit that value it must appear in the same select menu (select2) to select the value previously selected but I can't find a way.

UPDATE:

The HTML code:

<input type="hidden" name="programid" id="programid" class="width-500 validate[required]">

Answer 1

To set selected value of jQuery Select2 with JavaScript, we call val and then trigger . Then we set its value with val to the option with value 0. Finally, we call trigger with 'change' to update the drop down to show the value we set.