KeyboardEvent: 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 KeyboardEvent.altKey read-only property is a boolean value that indicates if the alt key (Option or ⌥ on macOS) was pressed (true) or not (false) when the event occurred.

Value

A boolean value.

Examples

html

<p>
  Press any character key, with or without holding down the ALT key.<br />
  You can also use the SHIFT key together with the ALT key.
</p>
<pre id="output"></pre>

const output = document.getElementById("output");

function showChar(e) {
  output.textContent = `Key KeyDown: "${e.key}"
ALT key KeyDown: ${e.altKey}
`;
}

document.addEventListener("keydown", showChar);