Web/API/Window/screenY

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 [[../../../../../../../mdn.github.io/dom-examples/screenleft-screentop/index|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 ModuleThe definition of 'Window.screenY' in that specification.	Working Draft	Initial definition.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`screenY`	Chrome Full support 1	Edge Full support 12	Firefox Full support 1 Notes' Full support 1 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 9	Opera Full support ≤12.1	Safari Full support 1	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4 Notes' Full support 4 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 ≤12.1	Safari iOS Full support 1	Samsung Internet Android Full support 1.0

Legend

Full support: Full support
See implementation notes.': See implementation notes.