MouseEvent: ctrlKey property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨July 2015⁩.

The MouseEvent.ctrlKey read-only property is a boolean value that indicates whether the ctrl key was pressed or not when a given mouse event occurs.

On Macintosh keyboards, this key is labeled the control key. Also, note that on a Mac, a click combined with the control key is intercepted by the operating system and used to open a context menu, so ctrlKey is not detectable on click events.

Pinch-zooming using a trackpad also sends a simulated wheel event with ctrlKey set to true.

<p id="log">The ctrl key was pressed while the cursor was moving: false</p>

JavaScript

const log = document.querySelector("#log");
window.addEventListener("mousemove", logKey);

function logKey(e) {
  log.textContent = `The ctrl key was pressed while the cursor was moving: ${e.ctrlKey}`;
}