HTML DOM crypto.getRandomValues() method

Namachila November 13, 2025

0 3 1 minute read

The crypto getRandomValues() method lets you get cryptographic random values. The array given as the parameter to this method gets filled with cryptographic random numbers.

Syntax:

var a = window.crypto.getRandomValues(Array);

Parameters:

Array: An integer-based Array, can be Int8Array, UInt8Array, Int16Array, Uint16Array, Int32Array, or Uint32Array. All elements in the array are overwritten with random numbers after using this method.

Return Value: The Array passed in this method is overwritten and returned.

Example: This example uses the getRandomValues() method to generate a random Uint32Array of size 10.

<!DOCTYPE HTML>  
<html>   
<head> 
    <title>crypto getRandomValues() method</title> 
</head>    
<body style="text-align:center;"> 
    <h1 style="color:green;">   
        GeeksForGeeks   
    </h1>  
    <p>  
    HTML | crypto getRandomValues() method     
    </p> 
    <button onclick = "Geeks();"> 
    click here 
    </button> 
    <p id="arr">  
    </p>        
    <script>  
        var arr = document.getElementById("arr"); 
        function Geeks() { 
            var array = new Uint32Array(10); 
            a = window.crypto.getRandomValues(array); 
            console.log(a); 
            arr.innerHTML =  
           "The randomly generated array is: "+a; 
        }  
    </script>  
</body>    
</html>