MouseEvent: altKey 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.altKey read-only property is a boolean value that indicates whether the alt key was pressed or not when a given mouse event occurs.
Be aware that the browser can't always detect the alt key on some operating systems. On some Linux variants, for example, a left mouse click combined with the alt key is used to move or resize windows.
Note: On Macintosh keyboards, this key is also known as the option key.
Value
A boolean value, where true indicates that the key is pressed, and false indicates that the key is not pressed.
Examples
This example logs the altKey property when you trigger a click event.
HTML
<p>Click anywhere to test the <code>altKey</code> property.</p>
<p id="log"></p>
JavaScript
let log = document.querySelector("#log");
document.addEventListener("click", logKey);
function logKey(e) {
log.textContent = `The alt key is pressed: ${e.altKey}`;
}
Result
Specifications
| Specification |
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| Pointer Events # dom-mouseevent-altkey |
Browser compatibility
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altKey
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Legend
Tip: you can click/tap on a cell for more information.
- Full support
- Full support