The Touch interface represents a single contact point on a touch-sensitive device. The contact point is commonly a finger or stylus and the device may be a touchscreen or trackpad.
The Touch.radiusX, Touch.radiusY, and Touch.rotationAngle describe the area of contact between the user and the screen, the touch area. This can be helpful when dealing with imprecise pointing devices such as fingers. These values are set to describe an ellipse that as closely as possible matches the entire area of contact (such as the user's fingertip).
Note: Many of the properties' values are hardware-dependent; for example, if the device doesn't have a way to detect the amount of pressure placed on the surface, the force value will always be 0. This may also be the case for radiusX and radiusY; if the hardware reports only a single point, these values will be 1.
Constructor
Touch()- Creates a Touch object.
Properties
This interface has no parent, and doesn't inherits or implements any other property.
Basic properties
Touch.identifierRead only- Returns a unique identifier for this
Touchobject. A given touch point (say, by a finger) will have the same identifier for the duration of its movement around the surface. This lets you ensure that you're tracking the same touch all the time. Touch.screenXRead only- Returns the X coordinate of the touch point relative to the left edge of the screen.
Touch.screenYRead only- Returns the Y coordinate of the touch point relative to the top edge of the screen.
Touch.clientXRead only- Returns the X coordinate of the touch point relative to the left edge of the browser viewport, not including any scroll offset.
Touch.clientYRead only- Returns the Y coordinate of the touch point relative to the top edge of the browser viewport, not including any scroll offset.
Touch.pageXRead only- Returns the X coordinate of the touch point relative to the left edge of the document. Unlike
clientX, this value includes the horizontal scroll offset, if any. Touch.pageYRead only- Returns the Y coordinate of the touch point relative to the top of the document. Unlike
clientY,this value includes the vertical scroll offset, if any. Touch.targetRead only- Returns the
Elementon which the touch point started when it was first placed on the surface, even if the touch point has since moved outside the interactive area of that element or even been removed from the document.
Touch area
This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
Touch.radiusXRead only- Returns the X radius of the ellipse that most closely circumscribes the area of contact with the screen. The value is in pixels of the same scale as
screenX. Touch.radiusYRead only- Returns the Y radius of the ellipse that most closely circumscribes the area of contact with the screen. The value is in pixels of the same scale as
screenY. Touch.rotationAngleRead only- Returns the angle (in degrees) that the ellipse described by radiusX and radiusY must be rotated, clockwise, to most accurately cover the area of contact between the user and the surface.
Touch.forceRead only- Returns the amount of pressure being applied to the surface by the user, as a
floatbetween0.0(no pressure) and1.0(maximum pressure).
Methods
This interface has no method and no parent, and doesn't inherits or implements any method.
Specifications
| Specification | Status | Comment |
|---|---|---|
| Touch Events – Level 2 The definition of 'Touch' in that specification. |
Editor's Draft | Added radiusX, radiusY, rotationAngle, force properties, as well as the Touch() constructor. |
| Touch Events The definition of 'Touch' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
| Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
|---|---|---|---|---|---|---|
| Basic support | 22.0 | (Yes) | 18.0 (18.0)[1] 52.0 (52.0)[2] |
No support | No support | No support |
radiusX, radiusY, rotationAngle, force |
? | ? | (Yes) | ? | ? | ? |
Touch() constructor |
? | No support | No support | ? | ? | ? |
| Feature | Android | Android Webview | Chrome for Android | Edge | Firefox Mobile (Gecko) | Firefox OS | IE Mobile | Opera Mobile | Safari Mobile |
|---|---|---|---|---|---|---|---|---|---|
| Basic support | (Yes) | (Yes) | (Yes) | (Yes) | 6.0 (6.0) | (Yes) | 11 | (Yes) | (Yes) |
radiusX, radiusY, rotationAngle, force |
? | ? | ? | ? | 6.0 (6.0) | (Yes) | ? | ? | ? |
Touch() constructor |
? | ? | No support | ? | No support | No support | ? | ? | ? |
[1] Touch events were implemented in Gecko 18.0, but removed again in 24.0 (Firefox 24.0 / Thunderbird 24.0 / SeaMonkey 2.21) on the desktop version of Firefox due to web compatibility issues (bug 888304).
[2] As of Gecko 52.0, touch events support has been fixed and reenabled in Windows desktop platforms.