How to set selected value of jQuery Select2?

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]">

Select2 programmatic access does not work with this.

> # SELECT2 < V4

---

Step #1: HTML

<input name="mySelect2" type="hidden" id="mySelect2">

Step #2: Create an instance of Select2

$("#mySelect2").select2({
      placeholder: "My Select 2",
      multiple: false,
      minimumInputLength: 1,
      ajax: {
          url: "/elements/all",
          dataType: 'json',
          quietMillis: 250,
          data: function(term, page) {
              return {
                  q: term,
              };
          },
          results: function(data, page) {
              return {results: data};
          },
          cache: true
      },
      formatResult: function(element){
          return element.text + ' (' + element.id + ')';
      },
      formatSelection: function(element){
          return element.text + ' (' + element.id + ')';
      },
      escapeMarkup: function(m) {
          return m;
      }
});

Step #3: Set your desired value

$("#mySelect2").select2('data', { id:"elementID", text: "Hello!"});

---

If you use select2 without AJAX you can do as follow:

<select name="mySelect2" id="mySelect2">
  <option value="0">One</option>
  <option value="1">Two</option>
  <option value="2">Three</option>
</select>

/* "One" will be the selected option */
$('[name=mySelect2]').val("0");

You can also do so:

$("#mySelect2").select2("val", "0");

---

> # SELECT2 V4

---

For select2 v4 you can append directly an option/s as follow:

<select id="myMultipleSelect2" multiple="" name="myMultipleSelect2[]">
    <option value="TheID" selected="selected">The text</option>                                                                   
</select>

Or with JQuery:

var $newOption = $("<option selected='selected'></option>").val("TheID").text("The text")
 
$("#myMultipleSelect2").append($newOption).trigger('change');

other example

$("#myMultipleSelect2").val(5).trigger('change');

To dynamically set the "selected" value of a Select2 component:

$('#inputID').select2('data', {id: 100, a_key: 'Lorem Ipsum'});

Where the second parameter is an object with expected values.

UPDATE:

This does work, just wanted to note that in the new select2, "a_key" is "text" in a standard select2 object. so: {id: 100, text: 'Lorem Ipsum'}

Example:

$('#all_contacts').select2('data', {id: '123', text: 'res_data.primary_email'});

Thanks to @NoobishPro

Html:

<select id="lang" >
   <option value="php">php</option>
   <option value="asp">asp</option>
   <option value="java">java</option>
</select>

JavaScript:

$("#lang").select2().select2('val','asp');

jsfiddle

Also as I tried, when use ajax in select2, the programmatic control methods for set new values in select2 does not work for me! Now I write these code for resolve the problem:

$('#sel')
    .empty() //empty select
    .append($("<option/>") //add option tag in select
        .val("20") //set value for option to post it
        .text("nabi")) //set a text for show in select
    .val("20") //select option of select2
    .trigger("change"); //apply to select2

You can test complete sample code in here link: https://jsfiddle.net/NabiKAZ/2g1qq26v/32/
In this sample code there is a ajax select2 and you can set new value with a button.

$("#btn").click(function() {
  $('#sel')
    .empty() //empty select
    .append($("<option/>") //add option tag in select
      .val("20") //set value for option to post it
      .text("nabi")) //set a text for show in select
    .val("20") //select option of select2
    .trigger("change"); //apply to select2
});

$("#sel").select2({
  ajax: {
    url: "https://api.github.com/search/repositories",
    dataType: 'json',
    delay: 250,
    data: function(params) {
      return {
        q: params.term, // search term
        page: params.page
      };
    },
    processResults: function(data, params) {
      // parse the results into the format expected by Select2
      // since we are using custom formatting functions we do not need to
      // alter the remote JSON data, except to indicate that infinite
      // scrolling can be used
      params.page = params.page || 1;

      return {
        results: data.items,
        pagination: {
          more: (params.page * 30) < data.total_count
        }
      };
    },
    cache: true
  },
  escapeMarkup: function(markup) {
    return markup;
  }, // let our custom formatter work
  minimumInputLength: 1,
  templateResult: formatRepo, // omitted for brevity, see the source of this page
  templateSelection: formatRepoSelection // omitted for brevity, see the source of this page
});

function formatRepo(repo) {
  if (repo.loading) return repo.text;

  var markup = "<div class='select2-result-repository clearfix'>" +
    "<div class='select2-result-repository__avatar'><img src='" + repo.owner.avatar_url + "' /></div>" +
    "<div class='select2-result-repository__meta'>" +
    "<div class='select2-result-repository__title'>" + repo.full_name + "</div>";

  if (repo.description) {
    markup += "<div class='select2-result-repository__description'>" + repo.description + "</div>";
  }

  markup += "<div class='select2-result-repository__statistics'>" +
    "<div class='select2-result-repository__forks'><i class='fa fa-flash'></i> " + repo.forks_count + " Forks</div>" +
    "<div class='select2-result-repository__stargazers'><i class='fa fa-star'></i> " + repo.stargazers_count + " Stars</div>" +
    "<div class='select2-result-repository__watchers'><i class='fa fa-eye'></i> " + repo.watchers_count + " Watchers</div>" +
    "</div>" +
    "</div></div>";

  return markup;
}

function formatRepoSelection(repo) {
  return repo.full_name || repo.text;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js"></script>
<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.2-rc.1/css/select2.min.css">
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.2-rc.1/js/select2.min.js"></script>
<link rel="stylesheet" type="text/css" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.min.css">
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.min.js"></script>
<link rel="stylesheet" type="text/css" href="https://select2.org/assets/a7be624d756ba99faa354e455aed250d.css">

<select id="sel" multiple="multiple" class="col-xs-5">
</select>

<button id="btn">Set Default</button>

I did like this-

$("#drpServices").select2().val("0").trigger("change");

var $option = $("<option selected></option>").val('1').text("Pick me");

$('#select_id').append($option).trigger('change');

Try this append then select. Doesn't duplicate the option upon AJAX call.

In the current version on select2 - v4.0.1 you can set the value like this:

var $example = $('.js-example-programmatic').select2();
$(".js-programmatic-set-val").on("click", function () { $example.val("CA").trigger("change"); });

// Option 2 if you can't trigger the change event.
var $exampleDestroy = $('.js-example-programmatic-destroy').select2();
$(".js-programmatic-set-val").on("click", function () { $exampleDestroy.val("CA").select2('destroy').select2(); });

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.1/js/select2.min.js"></script>
<link href="//cdnjs.cloudflare.com/ajax/libs/select2/4.0.1/css/select2.min.css" rel="stylesheet" />

using "trigger(change)"
<select class="js-example-programmatic">
  <optgroup label="Alaskan/Hawaiian Time Zone">
    <option value="AK">Alaska</option>
    <option value="HI">Hawaii</option>
  </optgroup>
  <optgroup label="Pacific Time Zone">
    <option value="CA">California</option>
    <option value="NV">Nevada</option>
    <option value="OR">Oregon</option>
    <option value="WA">Washington</option>
  </optgroup>
  <optgroup label="Mountain Time Zone">
    <option value="AZ">Arizona</option>
    <option value="CO">Colorado</option>
    <option value="ID">Idaho</option>
    <option value="MT">Montana</option>
    <option value="NE">Nebraska</option>
    <option value="NM">New Mexico</option>
    <option value="ND">North Dakota</option>
    <option value="UT">Utah</option>
    <option value="WY">Wyoming</option>
  </optgroup>
  <optgroup label="Central Time Zone">
    <option value="AL">Alabama</option>
    <option value="AR">Arkansas</option>
    <option value="IL">Illinois</option>
    <option value="IA">Iowa</option>
    <option value="KS">Kansas</option>
    <option value="KY">Kentucky</option>
    <option value="LA">Louisiana</option>
    <option value="MN">Minnesota</option>
    <option value="MS">Mississippi</option>
    <option value="MO">Missouri</option>
    <option value="OK">Oklahoma</option>
    <option value="SD">South Dakota</option>
    <option value="TX">Texas</option>
    <option value="TN">Tennessee</option>
    <option value="WI">Wisconsin</option>
  </optgroup>
  <optgroup label="Eastern Time Zone">
    <option value="CT">Connecticut</option>
    <option value="DE">Delaware</option>
    <option value="FL">Florida</option>
    <option value="GA">Georgia</option>
    <option value="IN">Indiana</option>
    <option value="ME">Maine</option>
    <option value="MD">Maryland</option>
    <option value="MA">Massachusetts</option>
    <option value="MI">Michigan</option>
    <option value="NH">New Hampshire</option>
    <option value="NJ">New Jersey</option>
    <option value="NY">New York</option>
    <option value="NC">North Carolina</option>
    <option value="OH">Ohio</option>
    <option value="PA">Pennsylvania</option>
    <option value="RI">Rhode Island</option>
    <option value="SC">South Carolina</option>
    <option value="VT">Vermont</option>
    <option value="VA">Virginia</option>
    <option value="WV">West Virginia</option>
  </optgroup>
</select>

using destroy: 
<select class="js-example-programmatic">
  <optgroup label="Alaskan/Hawaiian Time Zone">
    <option value="AK">Alaska</option>
    <option value="HI">Hawaii</option>
  </optgroup>
  <optgroup label="Pacific Time Zone">
    <option value="CA">California</option>
    <option value="NV">Nevada</option>
    <option value="OR">Oregon</option>
    <option value="WA">Washington</option>
  </optgroup>
  <optgroup label="Mountain Time Zone">
    <option value="AZ">Arizona</option>
    <option value="CO">Colorado</option>
    <option value="ID">Idaho</option>
    <option value="MT">Montana</option>
    <option value="NE">Nebraska</option>
    <option value="NM">New Mexico</option>
    <option value="ND">North Dakota</option>
    <option value="UT">Utah</option>
    <option value="WY">Wyoming</option>
  </optgroup>
  <optgroup label="Central Time Zone">
    <option value="AL">Alabama</option>
    <option value="AR">Arkansas</option>
    <option value="IL">Illinois</option>
    <option value="IA">Iowa</option>
    <option value="KS">Kansas</option>
    <option value="KY">Kentucky</option>
    <option value="LA">Louisiana</option>
    <option value="MN">Minnesota</option>
    <option value="MS">Mississippi</option>
    <option value="MO">Missouri</option>
    <option value="OK">Oklahoma</option>
    <option value="SD">South Dakota</option>
    <option value="TX">Texas</option>
    <option value="TN">Tennessee</option>
    <option value="WI">Wisconsin</option>
  </optgroup>
  <optgroup label="Eastern Time Zone">
    <option value="CT">Connecticut</option>
    <option value="DE">Delaware</option>
    <option value="FL">Florida</option>
    <option value="GA">Georgia</option>
    <option value="IN">Indiana</option>
    <option value="ME">Maine</option>
    <option value="MD">Maryland</option>
    <option value="MA">Massachusetts</option>
    <option value="MI">Michigan</option>
    <option value="NH">New Hampshire</option>
    <option value="NJ">New Jersey</option>
    <option value="NY">New York</option>
    <option value="NC">North Carolina</option>
    <option value="OH">Ohio</option>
    <option value="PA">Pennsylvania</option>
    <option value="RI">Rhode Island</option>
    <option value="SC">South Carolina</option>
    <option value="VT">Vermont</option>
    <option value="VA">Virginia</option>
    <option value="WV">West Virginia</option>
  </optgroup>
</select>

<button class="js-programmatic-set-val">set value</button>

I think you need the initSelection function

$("#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};
    }
  },
  initSelection: function (element, callback) {
    var id = $(element).val();
    if (id !== "") {
      $.ajax("ajax.php/get_where", {
        data: {programid: id},
        dataType: "json"
      }).done(function (data) {
        $.each(data, function (i, value) {
          callback({"text": value.text, "id": value.id});
        });
        ;
      });
    }
  },
  dropdownCssClass: "bigdrop",
  escapeMarkup: function (m) { return m; }
});

HTML

<select id="lang" >
   <option value="php">php</option>
   <option value="asp">asp</option>
   <option value="java">java</option>
</select>

JS

 $("#lang").select2().val('php').trigger('change.select2');

source: https://select2.github.io/options.html

Set the value and trigger the change event immediately.

$('#selectteam').val([183,182]).trigger('change');

$('#inputID').val("100").select2();

It would be more appropriate to apply select2 after choosing one of the current select.

In Select2 V.4

use $('selector').select2().val(value_to_select).trigger('change');

I think it should work

For Ajax, use $(".select2").val("").trigger("change"). That should solve the problem.

	$("#select_location_id").val(value);
	$("#select_location_id").select2().trigger('change');

I solved my problem with this simple code. Where #select_location_id is an ID of select box and value is value of an option listed in select2 box.

An Phan's answer worked for me:

$('#inputID').select2('data', {id: 100, a_key: 'Lorem Ipsum'});

But adding the change trigger the event

$('#inputID').select2('data', {id: 100, a_key: 'Lorem Ipsum'}).change();

Sometimes, select2() will be loading firstly, and that makes the control not to show previously selected value correctly. Putting a delay for some seconds can resolve this problem.

setTimeout(function(){					
    $('#costcentreid').select2();				
},3000);

you can use this code :

$("#programid").val(["number:2", "number:3"]).trigger("change");

where 2 in "number:2" and 3 in "number:3" are id field in object array

This work for me fine:

        initSelection: function (element, callback) {
    var id = $(element).val();
    $.ajax("url/" + id, {
        dataType: "json"
    }).done(function (data) {
        var newOption = new Option(data.title, data.id, true, true);
        $('#select2_id').append(newOption).trigger('change');
        callback({"text": data.title, "id": data.id});
    });
},

Preselecting options in an remotely-sourced (AJAX) Select2 For Select2 controls that receive their data from an AJAX source, using .val() will not work. The options won't exist yet, because the AJAX request is not fired until the control is opened and/or the user begins searching. This is further complicated by server-side filtering and pagination - there is no guarantee when a particular item will actually be loaded into the Select2 control!

The best way to deal with this, therefore, is to simply add the preselected item as a new option. For remotely sourced data, this will probably involve creating a new API endpoint in your server-side application that can retrieve individual items:

$('#mySelect2').select2({
ajax: {
    url: '/api/students'
}
});
var studentSelect = $('#mySelect2');
$.ajax({
    type: 'GET',
    url: '/api/students/s/' + studentId
}).then(function (data) {
// create the option and append to Select2
var option = new Option(data.full_name, data.id, true, true);
studentSelect.append(option).trigger('change');

// manually trigger the `select2:select` event
studentSelect.trigger({
    type: 'select2:select',
    params: {
        data: data
    }
});
});

I did something like this to preset elements in select2 ajax dropdown

      //preset element values
        $(id).val(topics);
       //topics is an array of format [{"id":"","text":""}, .....]
          setTimeout(function(){
           ajaxTopicDropdown(id,
                2,location.origin+"/api for gettings topics/",
                "Pick a topic", true, 5);                      
            },1);
        // ajaxtopicDropdown is dry fucntion to get topics for diffrent element and url

You should use:

var autocompleteIds= $("#EventId");
autocompleteIds.empty().append('<option value="Id">Text</option>').val("Id").trigger('change');

// For set multi selected values
var data =  [];//Array Ids
var option =  [];//Array options of Ids above
autocompleteIds.empty().append(option).val(data).trigger('change');

// Callback handler that will be called on success
request.done(function (response, textStatus, jqXHR) {
	// append the new option
	$("#EventId").append('<option value="' + response.id + '">' + response.text + '</option>');

	// get a list of selected values if any - or create an empty array
	var selectedValues = $("#EventId").val();
	if (selectedValues == null) {
		selectedValues = new Array();
	}
	selectedValues.push(response.id);   // add the newly created option to the list of selected items
	$("#EventId").val(selectedValues).trigger('change');   // have select2 do it's thing
});

If you are using an Input box, you must set the "multiple" property with its value as "true". For example,

<script>
    $(document).ready(function () {

        var arr = [{ id: 100, text: 'Lorem Ipsum 1' },
            { id: 200, text: 'Lorem Ipsum 2'}];

        $('#inputID').select2({
            data: arr,
            width: 200,
            multiple: true
        });
    });
</script>

In select2 < version4 there is the option initSelection() for remote data loading, through which it is possible to set initial value for the input as in edit mode.

$("#e6").select2({
    placeholder: "Search for a repository",
    minimumInputLength: 1,
    ajax: { 
        // instead of writing the function to execute the request we use Select2's convenient helper
        url: "https://api.github.com/search/repositories",
        dataType: 'json',
        quietMillis: 250,
        data: function (term, page) {
            return {
                q: term, // search term
            };
        },
        results: function (data, page) {
            // parse the results into the format expected by Select2.
            // since we are using custom formatting functions we do not need to alter the remote JSON data
            return { results: data.items };
        },
        cache: true
    },
    initSelection: function(element, callback) {
        // the input tag has a value attribute preloaded that points to a preselected repository's id
        // this function resolves that id attribute to an object that select2 can render
        // using its formatResult renderer - that way the repository name is shown preselected
        var id = $(element).val();
        if (id !== "") {
            $.ajax("https://api.github.com/repositories/" + id, {
                dataType: "json"
            }).done(function(data) { callback(data); });
        }
    },
    formatResult: repoFormatResult, // omitted for brevity, see the source of this page
    formatSelection: repoFormatSelection,  // omitted for brevity, see the source of this page
    dropdownCssClass: "bigdrop", // apply css that makes the dropdown taller
    escapeMarkup: function (m) { return m; } // we do not want to escape markup since we are displaying html in results
});

Source Documentation : Select2 - 3.5.3

You can use this code:

    $('#country').select2("val", "Your_value").trigger('change');

Put your desired value instead of Your_value

Hope It will work :)

Just to add to anyone else who may have come up with the same issue with me.

I was trying to set the selected option of my dynamically loaded options (from AJAX) and was trying to set one of the options as selected depending on some logic.

My issue came because I wasn't trying to set the selected option based on the ID which needs to match the value, not the value matching the name!

For multiple values something like this:

$("#HouseIds").select2("val", @Newtonsoft.Json.JsonConvert.SerializeObject(Model.HouseIds));

which will translate to something like this

$("#HouseIds").select2("val", [35293,49525]);

This may help someone loading select2 data from AJAX while loading data for editing (applicable for single or multi-select):

During my form/model load :

  $.ajax({
        type: "POST",
        ...        
        success: function (data) {
          selectCountries(fixedEncodeURI(data.countries));
         }

Call to select data for Select2:

var countrySelect = $('.select_country');
function selectCountries(countries)
    {
        if (countries) {
            $.ajax({
                type: 'GET',
                url: "/regions/getCountries/",
                data: $.param({ 'idsSelected': countries }, true),
                
            }).then(function (data) {
                // create the option and append to Select2                     
                $.each(data, function (index, value) {
                    var option = new Option(value.text, value.id, true, true);
                    countrySelect.append(option).trigger('change');
                    console.log(option);
                });
                // manually trigger the `select2:select` event
                countrySelect.trigger({
                    type: 'select2:select',
                    params: {
                        data: data
                    }
                });
            });
        }
    }

and if you may be having issues with encoding you may change as your requirement:

function fixedEncodeURI(str) {
        return encodeURI(str).replace(/%5B/g, '[').replace(/%5D/g, ']').replace(/%22/g,"");

    }

To build ontop of @tomloprod's answer. By the odd chance that you are using x-editable, and have a select2(v4) field and have multiple items you need to pre-select. You can use the following piece of code:

$("#select2field").on("shown", function(e, editable){
    $(["test1", "test2", "test3", "test4"]).each(function(k, v){
        // Create a DOM Option and pre-select by default~
        var newOption = new Option(v.text, v.id, true, true);
        // Append it to the select
        $(editable.input.$input).append(newOption).trigger('change');
     });
});

and here it is in action:

var data = [ { id: 0, text: 'enhancement' }, { id: 1, text: 'bug' }, { id: 2, text: 'duplicate' }, { id: 3, text: 'invalid' }, { id: 4, text: 'wontfix' } ];

$("#select2field").editable({
        type: "select2",
        url: './',
        name: 'select2field',
        savenochange: true,
        send: 'always',
        mode: 'inline',
        source: data,
        value: "bug, wontfix",
        tpl: '<select style="width: 201px;">',
        select2: {
            width: '201px',
            tags: true,
            tokenSeparators: [',', ' '],
            multiple: true,
            data:data
        },
        success: function(response, newValue) {
            console.log("success")
        },
        error: function(response, newValue) {
            if (response.status === 500) {
                return 'Service unavailable. Please try later.';
            } else {
                return response.responseJSON;
            }
        }
    });

var preselect= [
    {
        id: 1,
        text: 'bug'
    },
    {
    id: 4,
    text: 'wontfix'
}
];

 $("#select2field").on("shown", function(e, editable){
    $(preselect).each(function(k, v){
        // Create a DOM Option and pre-select by default~
        var newOption = new Option(v.text, v.id, true, true);
        // Append it to the select
        $(editable.input.$input).append(newOption).trigger('change');
     });
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/select2/4.0.1/js/select2.min.js"></script>
<link href="//cdnjs.cloudflare.com/ajax/libs/select2/4.0.1/css/select2.min.css" rel="stylesheet" />

bug, wontfix

I guess that this would work even if you aren't using x-editable. I hope that htis could help someone.

I use select2 with ajax source with Laravel. In my case it simple work cycling option i receive from page and add Option to select2..

$filtri->stato = [1,2,...];

$('#stato') is my select2 with server side load

<script>
    @foreach ($filtri->stato as $item)
       $('#stato').append(new Option("{{\App\Models\stato::find($item)->nome}}",{{$item}}, false, true));
    @endforeach
</script>

In my case I can call text of option with find method, but it's possible do it with ajax call

Official Select2 documentation says:

> For Select2 controls that receive their data from an AJAX source, using .val() will not work. The options won't exist yet, because the AJAX request is not fired until the control is opened and/or the user begins searching.

To set value in select2 field place <option> tag inside <select> tag during page rendering:

<select id="input-degree">
    <option value="1">Art</option>
</select>

When page is loaded you'll see Art in select2 field. If we click on this field data will be fetched from the server via ajax and other options will be shown.

[jsfiddle_link][1] <select id="lang" multiple >
       <option value="php">php</option>
        <option value="asp">asp</option>
       <option value="java">java</option>
  </select>

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

    $("#lang").select2().select2('val',['asp','php']);

<!-- language: lang-html -->


  [1]: https://jsfiddle.net/xrug7f6k/

if you are getting your values from ajax, before calling

$("#select_location_id").val(value);
$("#select_location_id").select2().trigger('change');

confirm that the ajax call has completed, using the jquery function when

$.when(ajax1(), ajax2(), ajax3(), ajax4()).done(function(a1, a2, a3, a4){
      // the code here will be executed when all four ajax requests resolve.
      // a1, a2, a3 and a4 are lists of length 3 containing the response text,
      // status, and jqXHR object for each of the four ajax calls respectively.
    }); 

as described here [https://stackoverflow.com/questions/3709597/wait-until-all-jquery-ajax-requests-are-done][1]

Nice and easy:

document.getElementById("select2-id_city-container").innerHTML = "Your Text Here";

And you change id_city to your select's id.

Edit: After Glen's comment I realize I should explain why and how it worked for me:

I had made select2 working really nice for my form. The only thing I couldn't make work was to show the current selected value when editing. It was searching a third party API, saving new and editing old records. After a while I realized I didn't need to set the value correctly, only the label inside field, because if the user doesn't change the field, nothing happens. After searching and looking to a lot of people having trouble with it, I decided make it with pure Javascript. It worked and I posted to maybe help someone. I also suggest to set a timer for it.