Tag Archives: limit select2 selection by group

Limit Select2 to one selection per optgroup with multiple selection

Here is a example to create multiple select with grouped multiple select where you can select one option per group.

HTML code

<pre class="wp-block-syntaxhighlighter-code">
&amp;lt;select multiple style=&quot;width: 300px&quot;&gt;
  &amp;lt;optgroup label=&quot;Alaskan/Hawaiian Time Zone&quot;&gt;
    &amp;lt;option groupid=&quot;a&quot; value=&quot;AK&quot;&gt;Alaska&amp;lt;/option&gt;
    &amp;lt;option groupid=&quot;a&quot; value=&quot;HI&quot;&gt;Hawaii&amp;lt;/option&gt;
  &amp;lt;optgroup label=&quot;Pacific Time Zone&quot;&gt;
    &amp;lt;option groupid=&quot;b&quot; value=&quot;CA&quot;&gt;California&amp;lt;/option&gt;
    &amp;lt;option groupid=&quot;b&quot; value=&quot;NV&quot;&gt;Nevada&amp;lt;/option&gt;
    &amp;lt;option groupid=&quot;b&quot; value=&quot;OR&quot;&gt;Oregon&amp;lt;/option&gt;
    &amp;lt;option groupid=&quot;b&quot; value=&quot;WA&quot;&gt;Washington&amp;lt;/option&gt;


JavaScript Code

$(function() {
      allowClear: true,
      placeholder: "Pick a State"

    //Select2 Event handler for selecting an item
    $('select').on("select2:selecting", function(evt, f, g) {
      disableSel2Group(evt, this, true);

    // Select2 Event handler for unselecting an item
    $('select').on("select2:unselecting", function(evt) {
      disableSel2Group(evt, this, false);

  // At some point during the select2 instantation it created the 
  // data object it needs with the source select option.
  // This function, called by the events above to set the current status for the
  // group for which the selected option belongs.
  function disableSel2Group(evt, target, disabled) {
    // Found a note in the Select2 formums on how to get the item to be selected

    var selId = evt.params.args.data.id;
    var group = $("option[value='" + selId + "']").attr("groupid");

    var aaList = $("option", target);
    $.each(aaList, function(idx, item) {
      var data = $(item).data("data");

      var itemGroupId = $("option[value='" + data.id + "']").attr("groupid");
      if (itemGroupId == group && data.id != selId) {
        data.disabled = disabled;

Check demo here