| `closeOnSelect` | boolean | `true` | Controls whether the dropdown is [closed after a selection is made](/dropdown#forcing-the-dropdown-to-remain-open-after-selection). |
| `dropdownParent` | jQuery selector or DOM node | `$(document.body)` | Allows you to [customize placement](/dropdown#dropdown-placement) of the dropdown. |
| `escapeMarkup` | callback | `Utils.escapeMarkup` | Handles [automatic escaping of content rendered by custom templates](/dropdown#built-in-escaping). |
| `initSelection` | callback | | See [`initSelection`](/upgrading/migrating-from-35#removed-the-requirement-of-initselection). **This option was deprecated in Select2 v4.0, and will be removed in v4.1.** |
| `maximumInputLength` | integer | `0` | [Maximum number of characters](/searching#maximum-search-term-length) that may be provided for a search term. |
| `maximumSelectionLength` | integer | `0` | The maximum number of items that may be selected in a multi-select control. If the value of this option is less than 1, the number of selected items will not be limited.
| `minimumInputLength` | integer | `0` | [Minimum number of characters required to start a search.](/searching#minimum-search-term-length) |
| `minimumResultsForSearch` | integer | `0` | The minimum number of results required to [display the search box](/searching#limiting-display-of-the-search-box-to-large-result-sets). |
| `multiple` | boolean | `false` | This option enables multi-select (pillbox) mode. Select2 will automatically map the value of the `multiple` HTML attribute to this option during initialization. |
| `placeholder` | string or object | `null` | Specifies the [placeholder](/placeholders) for the control. |
| `query` | A function taking `params` (including a `callback`) | `Query` | **This option was deprecated in Select2 v4.0, and will be removed in v4.1.** |
| `resultsAdapter` | | `ResultsAdapter` | Used to override the built-in [ResultsAdapter](/advanced/default-adapters/results). |
| `selectionAdapter` | | `SingleSelection` or `MultipleSelection`, depending on the value of `multiple`. | Used to override the built-in [SelectionAdapter](/advanced/default-adapters/selection). |
| `selectOnClose` | boolean | `false` | Implements [automatic selection](/dropdown#automatic-selection) when the dropdown is closed. |