The TouchEvent
interface represents an UIEvent
which is sent when the state of contacts with a touch-sensitive surface changes. This surface can be a touch screen or trackpad, for example. The event can describe one or more points of contact with the screen and includes support for detecting movement, addition and removal of contact points, and so forth.
Touches are represented by the Touch
object; each touch is described by a position, size and shape, amount of pressure, and target element. Lists of touches are represented by TouchList
objects.
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Constructor
TouchEvent()
- Creates a
TouchEvent
object.
Properties
This interface inherits properties from its parent, UIEvent
and Event
.
TouchEvent.altKey
Read only- A Boolean value indicating whether or not the alt key was down when the touch event was fired.
TouchEvent.changedTouches
Read only- A
TouchList
of all theTouch
objects representing individual points of contact whose states changed between the previous touch event and this one. TouchEvent.ctrlKey
Read only- A Boolean value indicating whether or not the control key was down when the touch event was fired.
TouchEvent.metaKey
Read only- A Boolean value indicating whether or not the meta key was down when the touch event was fired.
TouchEvent.shiftKey
Read only- A Boolean value indicating whether or not the shift key was down when the touch event was fired.
TouchEvent.targetTouches
Read only- A
TouchList
of all theTouch
objects that are both currently in contact with the touch surface and were also started on the same element that is the target of the event. TouchEvent.touches
Read only- A
TouchList
of all theTouch
objects representing all current points of contact with the surface, regardless of target or changed status. TouchEvent.rotation
Read only- Change in rotation (in degrees) since the event's beginning. Positive values indicate clockwise rotation; negative values indicate anticlockwise rotation. Initial value:
0.0
TouchEvent.scale
Read only- Distance between two digits since the event's beginning. Expressed as a floating-point multiple of the initial distance between the digits at the beginning of the event. Values below 1.0 indicate an inward pinch (zoom out). Values above 1.0 indicate an outward unpinch (zoom in). Initial value:
1.0
Touch event types
There are several types of event that can be fired to indicate that touch-related changes have occurred. You can determine which of these has happened by looking at the event's TouchEvent.type
property.
touchstart
Sent when the user places a touch point on the touch surface. The event's target will be the element
in which the touch occurred.
touchend
Sent when the user removes a touch point from the surface (that is, when they lift a finger or stylus from the surface). This is also sent if the touch point moves off the edge of the surface; for example, if the user's finger slides off the edge of the screen.
The event's target is the same element
that received the touchstart
event corresponding to the touch point, even if the touch point has moved outside that element.
The touch point (or points) that were removed from the surface can be found in the TouchList
specified by the changedTouches
attribute.
touchmove
Sent when the user moves a touch point along the surface. The event's target is the same element
that received the touchstart
event corresponding to the touch point, even if the touch point has moved outside that element.
This event is also sent if the values of the radius, rotation angle, or force attributes of a touch point change.
touchmove
events is sent is browser-specific, and may also vary depending on the capability of the user's hardware. You must not rely on a specific granularity of these events.touchcancel
Sent when a touch point has been disrupted in some way. There are several possible reasons why this might happen (and the exact reasons will vary from device to device, as well as browser to browser):
- An event of some kind occurred that canceled the touch; this might happen if a modal alert pops up during the interaction.
- The touch point has left the document window and moved into the browser's UI area, a plug-in, or other external content.
- The user has placed more touch points on the screen than can be supported, in which case the earliest
Touch
in theTouchList
gets canceled.
Using with addEventListener() and preventDefault()
It's important to note that in many cases, both touch and mouse events get sent (in order to let non-touch-specific code still interact with the user). If you use touch events, you should call preventDefault()
to keep the mouse event from being sent as well.
The exception to this is Chrome, starting with version 56 (desktop, Chrome for android, and android webview), where the default value for the passive
option for touchstart
and touchmove
is true
and calls to preventDefault()
will have no effect. To override this behavior, you need to set the passive
option to false
, after which calling preventDefault()
will work as specified. The change to treat listeners as passive
by default prevents the listener from blocking page rendering while a user is scrolling. A demo is available on the Google Developer site.
GlobalEventHandlers
The GlobalEventHandlers
mixin defines these events as global events that are available on any element in the DOM that the user can interact with.
GlobalEventHandlers.ontouchstart
- A global event handler for the
touchstart
event. GlobalEventHandlers.ontouchend
- A global event handler for the
touchend
event. GlobalEventHandlers.ontouchmove
- A global event handler for the
touchmove
event. GlobalEventHandlers.ontouchcancel
- A global event handler for the
touchcancel
event.
Example
See the example on the main Touch events article.
Specifications
Specification | Status | Comment |
---|---|---|
Touch Events – Level 2 The definition of 'TouchEvent' in that specification. |
Draft | Added ontouchstart , ontouchend , ontouchmove , ontouchend global attribute handlers |
Touch Events The definition of 'TouchEvent' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
TouchEvent | Chrome Full support 22 | Edge
Full support
79
| Firefox
Full support
52
| IE No support No | Opera Full support 15 | Safari No support No | WebView Android Full support ≤37 | Chrome Android Full support 25 | Firefox Android Full support 6 | Opera Android Full support 14 | Safari iOS Full support Yes | Samsung Internet Android Full support 1.5 |
TouchEvent() constructor | Chrome
Full support
48
| Edge
Full support
≤79
| Firefox ? | IE No support No | Opera Full support Yes | Safari No support No | WebView Android
Full support
48
| Chrome Android
Full support
48
| Firefox Android Full support Yes | Opera Android Full support Yes | Safari iOS Full support 3.2 | Samsung Internet Android
Full support
5.0
|
altKey | Chrome Full support 22 | Edge Full support ≤18 | Firefox
Full support
52
| IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 6 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
changedTouches | Chrome Full support 22 | Edge Full support ≤18 | Firefox
Full support
52
| IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 6 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
ctrlKey | Chrome Full support 22 | Edge Full support ≤18 | Firefox
Full support
52
| IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 6 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
metaKey | Chrome Full support 22 | Edge Full support ≤18 | Firefox
Full support
52
| IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 6 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
shiftKey | Chrome Full support 22 | Edge Full support ≤18 | Firefox
Full support
52
| IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 6 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
targetTouches | Chrome Full support 22 | Edge Full support ≤18 | Firefox
Full support
52
| IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 6 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
touches | Chrome Full support 22 | Edge Full support ≤18 | Firefox
Full support
52
| IE No support No | Opera Full support Yes | Safari No support No | WebView Android Full support Yes | Chrome Android Full support Yes | Firefox Android Full support 6 | Opera Android Full support Yes | Safari iOS Full support Yes | Samsung Internet Android Full support Yes |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- See implementation notes.
- See implementation notes.
- User must explicitly enable this feature.
- User must explicitly enable this feature.