HTML DOM | KeyboardEvent altKey Property

The KeyboardEvent altKey property in HTML DOM is a read-only property and used to return the boolean value which indicates the alt key is pressed or not. It returns True if alt key is pressed otherwise return false.



Below program illustrates the KeyboardEvent altkey property in HTML:

Example: This example check whether the “ALT” key is pressed or not.





<!DOCTYPE html>
        HTML DOM KeyboardEvent altKey property
    <h2>KeyboardEvent altKey Property</h2>
        Check whether the alt key is pressed or not
    <input type="text" onkeydown="keyboard(event)">
    <p id = "test"></p>
    <!-- script to check alt key event -->
        function keyboard(event) {
            var a = document.getElementById("test");
            if (event.altKey) {
                a.innerHTML = "The ALT key has been pressed!";
            else {
                a.innerHTML = "The ALT key has not been pressed!";


Before Press the Key:

After Press the key:

Supported Browsers: The browser supported by KeyboardEvent altKey property are listed below:

  • Opera
  • Internet Explorer
  • Google Chrome
  • Firefox
  • Apple Safari

My Personal Notes arrow_drop_up

I am a technology enthusiast who has a keen interest in programming I am pursuing Engineering in Computer Science from GEU, Dehradun I like to unwind by watching movies and English sitcomsI have a keen interest in music

If you like GeeksforGeeks and would like to contribute, you can also write an article using or mail your article to See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :
Practice Tags :

Be the First to upvote.

Please write to us at to report any issue with the above content.