Can Select2 be used with a <select> tag?

Select2 was designed to be a replacement for the standard <select> boxes that are displayed by the browser, so by default it supports all options and operations that are available in a standard select box, but with added flexibility. There is no special configuration required to make Select2 work with a <select> tag.

Does Select2 support nesting options?

A standard <select> box can display nested options by wrapping them with in an <optgroup> tag.

<select>
  <optgroup label="Group Name">
    <option>Nested option</option>
  </optgroup>
</select>

How many levels of nesting can there be?

Only a single level of nesting is allowed per the HTML specification. If you nest an <optgroup> within another <optgroup>, Select2 will not be able to detect the extra level of nesting and errors may be triggered as a result.

Can <optgroup> tags be made selectable?

No. This is a limitation of the HTML specification and is not a limitation that Select2 can overcome. You can emulate grouping by using an <option> instead of an <optgroup> and changing the style by using CSS, but this is not recommended as it is not fully accessible.

How are <option> and <optgroup> tags serialized into data objects?

Select2 will convert the <option> tag into a data object based on the following rules.

{
  "id": "value attribute" || "option text",
  "text": "label attribute" || "option text",
  "element": HTMLOptionElement
}

And <optgroup> tags will be converted into data objects using the following rules

{
  "text": "label attribute",
  "children": [ option data object, ... ],
  "elment": HTMLOptGroupElement
}