select2/docs/pages/01.getting-started/02.basic-usage/docs.md

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Basic usage	category docs	twig true	true

Single select boxes

Select2 was designed to be a replacement for the standard <select> box that is displayed by the browser. By default it supports all options and operations that are available in a standard select box, but with added flexibility.

Select2 can take a regular select box like this...

and turn it into this...

<select class="js-example-basic-single" name="state">
  <option value="AL">Alabama</option>
    ...
  <option value="WY">Wyoming</option>
</select>

Select2 will register itself as a jQuery function if you use any of the distribution builds, so you can call .select2() on any jQuery selector where you would like to initialize Select2.

// In your Javascript (external .js resource or <script> tag)
$(document).ready(function() {
    $('.js-example-basic-single').select2();
});

The DOM cannot be safely manipulated until it is "ready". To make sure that your DOM is ready before the browser initializes the Select2 control, wrap your code in a $(document).ready() block. Only one $(document).ready() block is needed per page.

Multi-select boxes (pillbox)

Select2 also supports multi-value select boxes. The select below is declared with the multiple attribute.

In your HTML:

<select class="js-example-basic-multiple" name="states[]" multiple="multiple">
  <option value="AL">Alabama</option>
    ...
  <option value="WY">Wyoming</option>
</select>

In your Javascript (external .js resource or <script> tag):

$(document).ready(function() {
    $('.js-example-basic-multiple').select2();
});