The Window.screenY read-only property returns the vertical distance, in CSS pixels, of the top border of the user's browser viewport to the top edge of the screen.

Note: An alias of screenY was implemented across modern browsers in more recent times — Window.screenTop. This was originally supported only in IE but was introduced everywhere due to popularity.

Syntax

topWindowPos = window.screenY 

Returns

A number equal to the number of CSS pixels from the top edge of the browser viewport to the  top edge of the screen.

Examples

In our screenleft-screentop example, you'll see a canvas onto which has been drawn a circle. In this example we are using Window.screenLeft/Window.screenTop plus Window.requestAnimationFrame() to constantly redraw the circle in the same physical position on the screen, even if the window position is moved.

initialLeft = window.screenLeft + canvasElem.offsetLeft;
initialTop = window.screenTop + canvasElem.offsetTop;

function positionElem() {
  let newLeft = window.screenLeft + canvasElem.offsetLeft;
  let newTop = window.screenTop + canvasElem.offsetTop;

  let leftUpdate = initialLeft - newLeft;
  let topUpdate = initialTop - newTop;

  ctx.fillStyle = 'rgb(0, 0, 0)';
  ctx.fillRect(0, 0, width, height);
  ctx.fillStyle = 'rgb(0, 0, 255)';
  ctx.beginPath();
  ctx.arc(leftUpdate + (width/2), topUpdate + (height/2) + 35, 50, degToRad(0), degToRad(360), false);
  ctx.fill();

  pElem.textContent = 'Window.screenLeft: ' + window.screenLeft + ', Window.screenTop: ' + window.screenTop;

  window.requestAnimationFrame(positionElem);
}

window.requestAnimationFrame(positionElem);

These work in exactly the same way as screenX/screenY.

Also in the code we include a snippet that detects whether screenLeft is supported, and if not, polyfills in screenLeft/screenTop using screenX/screenY.

if(!window.screenLeft) {
  window.screenLeft = window.screenX;
  window.screenTop = window.screenY;
}

Specifications

Specification Status Comment
CSS Object Model (CSSOM) View Module
The definition of 'Window.screenY' in that specification.
Working Draft Initial definition.

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic supportChrome Full support YesEdge Full support YesFirefox Full support Yes
Notes
Full support Yes
Notes
Notes Before Firefox 28, Gecko was using device pixels instead of CSS pixels; in other words, it was assuming a value of screenPixelsPerCSSPixel of 1 for any device.
IE Full support YesOpera Full support YesSafari Full support YesWebView Android Full support YesChrome Android Full support YesEdge Mobile Full support YesFirefox Android Full support Yes
Notes
Full support Yes
Notes
Notes Before Firefox 28, Gecko was using device pixels instead of CSS pixels; in other words, it was assuming a value of screenPixelsPerCSSPixel of 1 for any device.
Opera Android Full support YesSafari iOS Full support YesSamsung Internet Android ?

Legend

Full support  
Full support
Compatibility unknown  
Compatibility unknown
See implementation notes.
See implementation notes.

See also

Document Tags and Contributors

Last updated by: chrisdavidmills,