Web/API/MouseEvent/clientX

The clientX read-only property of the MouseEvent interface provides the horizontal coordinate within the application's viewport at which the event occurred (as opposed to the coordinate within the page).

For example, clicking on the left edge of the viewport will always result in a mouse event with a clientX value of 0, regardless of whether the page is scrolled horizontally.

Syntax

var x = instanceOfMouseEvent.clientX

Return value

A double floating point value, as redefined by the CSSOM View Module. Originally, this property was defined as a long integer. See the "Browser compatibility" section for details.

Example

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

Specifications

Specification	Status	Comment
CSS Object Model (CSSOM) View ModuleThe definition of 'clientX' in that specification.	Working Draft	Redefines `MouseEvent` from `long` to `double`.
Document Object Model (DOM) Level 3 Events SpecificationThe definition of 'MouseEvent.clientX' in that specification.	Obsolete	No change from Document Object Model (DOM) Level 2 Events Specification.
Document Object Model (DOM) Level 2 Events SpecificationThe definition of 'MouseEvent.clientX' in that specification.	Obsolete	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
`clientX`	Chrome Full support 1	Edge Full support 12	Firefox Full support 1	IE Full support 9	Opera Full support 10.6	Safari Full support 3.1	WebView Android Full support 1	Chrome Android Full support 18	Firefox Android Full support 4	Opera Android Full support 11	Safari iOS Full support 2	Samsung Internet Android Full support 1.0
Value type changed from `long` to `double`	Chrome Full support 56	Edge Full support ≤79	Firefox ?	IE ?	Opera ?	Safari ?	WebView Android Full support 56	Chrome Android Full support 56	Firefox Android ?	Opera Android ?	Safari iOS ?	Samsung Internet Android Full support 6.0

Legend

Full support: Full support
Compatibility unknown: Compatibility unknown