# Class: Control

This documentation is for OpenLayers v10.9.0. The latest is v.

## ol/control/Control~Control

    import Control from 'ol/control/Control.js';

A control is a visible widget with a DOM element in a fixed position on the screen. They can involve user input (buttons), or be informational only; the position is determined using CSS. By default these are placed in the container with CSS class name `ol-overlaycontainer-stopevent`, but can use any outside DOM element.

This is the base class for controls. You can use it for simple custom controls by creating the element with listeners, creating an instance:

    const myControl = new Control({element: myElement});

and then adding this to the map.

The main advantage of having this as a control rather than a simple separate DOM element is that preventing propagation is handled for you. Controls will also be objects in a `Collection`, so you can use their methods.

You can also extend this base for your own control class. See examples/custom-controls for an example of how to do this.

#### new Control(options)

control/Control.js, line 45

  Name | Type | Description
  --- | --- | ---
  `element` | HTMLElement | undefined | The element is the control's container element. This only needs to be specified if you're developing a custom control.
  `render` | function | undefined | Function called when the control should be re-rendered. This is called in a `requestAnimationFrame` callback.
  `target` | HTMLElement | string | undefined | Specify a target if you want the control to be rendered outside of the map's viewport.

  ##### Fires:

  - `change` (BaseEvent) - Generic change event. Triggered when the revision counter is increased.
  - `error` (BaseEvent) - Generic error event. Triggered when an error occurs.
  - `propertychange` (ObjectEvent) - Triggered when a property is changed.

### Subclasses

- Attribution
- FullScreen
- MousePosition
- OverviewMap
- Rotate
- ScaleLine
- ZoomSlider
- ZoomToExtent
- Zoom

### Extends

- BaseObject

### Methods

#### changed() inherited

Observable.js, line 68

  Increases the revision counter and dispatches a 'change' event.

#### dispatchEvent(event){boolean | undefined} inherited

events/Target.js, line 85

  Dispatches an event and calls all listeners listening for events of this type. The event parameter can either be a string or an Object with a `type` property.

  Name | Type | Description
  --- | --- | ---
  `event` | BaseEvent | string | Event object.

  ##### Returns:

  `false` if anyone called preventDefault on the event object or if any of the listeners returned false.

#### get(key){*} inherited

Object.js, line 136

  Gets a value.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.

  ##### Returns:

  Value.

#### getKeys(){Array.<string>} inherited

Object.js, line 149

  Get a list of object property names.

  ##### Returns:

  List of property names.

#### getMap(){Map | null}

control/Control.js, line 104

  Get the map associated with this control.

  ##### Returns:

  Map.

#### getProperties(){NoInfer.<Properties>} inherited

Object.js, line 158

  Get an object of all property names and values.

  ##### Returns:

  Object.

#### getRevision(){number} inherited

Observable.js, line 79

  Get the version number for this object. Each time the object is modified, its version number will be incremented.

  ##### Returns:

  Revision.

#### on(type, listener){EventsKey | Array<EventsKey>} inherited

Observable.js, line 152

  Listen for a certain type of event.

  Name | Type | Description
  --- | --- | ---
  `type` | string | Array.<string> | The event type or array of event types.
  `listener` | function | The listener function.

  ##### Returns:

  Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

#### once(type, listener){EventsKey | Array<EventsKey>} inherited

Observable.js, line 164

  Listen once for a certain type of event.

  Name | Type | Description
  --- | --- | ---
  `type` | string | Array.<string> | The event type or array of event types.
  `listener` | function | The listener function.

  ##### Returns:

  Unique key for the listener. If called with an array of event types as the first argument, the return will be an array of keys.

#### render(mapEvent)

control/Control.js, line 144

  Renders the control.

  Name | Type | Description
  --- | --- | ---
  `mapEvent` | MapEvent | Map event.

#### set(key, value, silent) inherited

Object.js, line 218

  Sets a value.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.
  `value` | * | Value.
  `silent` | boolean | undefined | Update without triggering an event.

#### setMap(map)

control/Control.js, line 116

  Remove the control from its current map and attach it to the new map. Pass `null` to just remove the control from the current map. Subclasses may set up event handlers to get notified about changes to the map here.

  Name | Type | Description
  --- | --- | ---
  `map` | Map | null | Map.

#### setProperties(values, silent) inherited

Object.js, line 238

  Sets a collection of key-value pairs. Note that this changes any existing properties and adds new ones (it does not remove any existing properties).

  Name | Type | Description
  --- | --- | ---
  `values` | Partial.<NoInfer.<Properties>> | Values.
  `silent` | boolean | undefined | Update without triggering an event.

#### setTarget(target)

control/Control.js, line 155

  This function is used to set a target element for the control. It has no effect if it is called after the control has been added to the map (i.e. after `setMap` is called on the control). If no `target` is set in the options passed to the control constructor and if `setTarget` is not called then the control is added to the map's overlay container.

  Name | Type | Description
  --- | --- | ---
  `target` | HTMLElement | string | Target.

#### un(type, listener) inherited

Observable.js, line 173

  Unlisten for a certain type of event.

  Name | Type | Description
  --- | --- | ---
  `type` | string | Array.<string> | The event type or array of event types.
  `listener` | function | The listener function.

#### unset(key, silent) inherited

Object.js, line 262

  Unsets a property.

  Name | Type | Description
  --- | --- | ---
  `key` | string | Key name.
  `silent` | boolean | undefined | Unset without triggering an event.