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.
A boolean value, where true indicates that the key is pressed, and false indicates that the key is not pressed.
This example logs the ctrlKey property when you trigger a mousemove event.
html
<p id="log">The ctrl key was pressed while the cursor was moving: false</p>
js
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}`;
}
| Specification |
|---|
| UI Events # dom-mouseevent-ctrlkey |
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
ctrlKey |
1 | 12 | 1.5 | 9 | ≤12.1 | 1 | ≤37 | 18 | 4 | ≤12.1 | 1 | 1.0 |
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https://developer.mozilla.org/en-US/docs/Web/API/MouseEvent/ctrlKey