JavaScript MouseEvent altKey Property

Last Updated : 08 Feb, 2023

The mouseEvent altKey property is used to define whether the alt key is pressed or not. It is a boolean value. When the alt key is pressed then on click of the mouse buttons it returns true and if it is not pressed then it returns false.

Syntax:

event.altKey

Return Value: It returns a boolean value indicating whether the alt key is pressed or not.

true: it indicates the alt key is pressed
false: it indicates the alt key is not pressed

Example: In this example, we will see the example of MouseEvent altKey property.

html

<body style="text-align:center;"> 
  
    <h1 style="color:green;"> 
        GeeksforGeeks 
    </h1> 
  
    <h2> 
        mouseEvent altKey Property 
    </h2> 
  
    <button onclick="geek (event);">Get Alt key state!</button> 
    <p id="gfg"></p> 
    <script> 
        function geek(event) { 
            if (event.altKey) { 
                document.getElementById("gfg") 
                        .innerHTML = "Alt key is pressed."; 
            } else { 
                document.getElementById("gfg") 
                        .innerHTML ="Alt key is not pressed."; 
            } 
        } 
    </script> 
</body>