Touch.screenX - Web APIs 编辑

Summary

Returns the X coordinate of the touch point relative to the screen, not including any scroll offset.

Syntax

var x = touchItem.screenX;

Return value

x

The X coordinate of the touch point relative to the screen, not including any scroll offset.

Example

This example illustrates how to access the Touch object's Touch.screenX and Touch.screenY properties. The Touch.screenX property is the horizontal (x) coordinate of a touch point relative to the screen in CSS pixels. The Touch.screenY property is the vertical coordinate of a touch point relative to the screen in CSS pixels.

In following simple code snippet, we assume the user initiates multiple touch contacts on an element with an id of source and then releases contacts with the surface. When the touchstart event handler is invoked, each touch point's Touch.screenX and Touch.screenY coordinates are accessed.

// Register a touchstart listeners for the 'source' element
var src = document.getElementById("source");

src.addEventListener('touchstart', function(e) {
  // Iterate through the touch points and log each screenX/Y coordinate.
  // The unit of each coordinate is CSS pixels.
  var i;
  for (i=0; i < e.touches.length; i++) {
    console.log("touchpoint[" + i + "].screenX = " + e.touches[i].screenX);
    console.log("touchpoint[" + i + "].screenY = " + e.touches[i].screenY);
  }
}, false);

Specifications

Browser compatibility

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