Window: screenLeft property
Baseline
Widely available
*
This feature is well established and works across many devices and browser versions. It’s been available across browsers since December 2018.
* Some parts of this feature may have varying levels of support.
The Window.screenLeft read-only property returns the
horizontal distance, in CSS pixels, from the left border of the user's browser viewport
to the left side of the screen.
Note:
screenLeft is an alias of the older
Window.screenX property. screenLeft was originally
supported only in IE but was introduced everywhere due to popularity.
Value
A number equal to the number of CSS pixels from the left edge of the browser viewport to the left 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 screenLeft/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);
Also in the code we include a snippet that detects whether screenLeft is
supported, and if not, polyfills in screenLeft/screenTop using
Window.screenX/Window.screenY.
if (!window.screenLeft) {
window.screenLeft = window.screenX;
window.screenTop = window.screenY;
}
Specifications
| Specification |
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| CSSOM View Module # dom-window-screenleft |
Browser compatibility
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screenLeft
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Relative to the Multi-screen origin
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support
- Partial support
- Partial support
- No support
- No support