MouseEvent.screenX

The screenX read-only property of the MouseEvent interface provides the horizontal coordinate (offset) of the mouse pointer in global (screen) coordinates.

var x = instanceOfMouseEvent.screenX

A double floating point value. Early versions of the spec defined this as an integer referring to the number of pixels. See the "Browser compatibility" section for details.

This example displays your mouse's coordinates whenever you trigger the mousemove event.

HTML

<p>Move your mouse to see its position.</p>
<p id="screen-log"></p>

JavaScript

let screenLog = document.querySelector('#screen-log');
document.addEventListener('mousemove', logKey);

function logKey(e) {
  screenLog.innerText = `
    Screen X/Y: ${e.screenX}, ${e.screenY}
    Client X/Y: ${e.clientX}, ${e.clientY}`;
}

Result

When you trap events on the window, document, or other roomy elements, you can get the coordinates of that event (e.g., a click) and route it properly, as the following example demonstrates:

function checkClickMap(e) {
  if (e.screenX < 50) doRedButton();
  if (50 <= e.screenX && e.screenX < 100) doYellowButton();
  if (e.screenX >= 100) doRedButton();
}

• MouseEvent
• screenY
• clientX / clientY