HTML DOM Window atob( ) Method

Last Updated : 15 Jun, 2023

The Window atob() method is used for decoding a base-64 encoded string. It is used to decode a string of data which has been encoded using the btoa() method. It returns a string which represents the decoded string.

Syntax :

window.atob(EncodedString)

Parameters Used :

EncodedString : It is a mandatory parameter which specifies the encoded string.

Below program illustrates the Window atob() Method :

Decoding a string encoded using the btoa() method.

html

<!DOCTYPE html> 
<html> 
  
<head> 
    <title> 
      Window atob() Method in HTML 
    </title> 
    <style> 
        h1 { 
            color: green; 
        } 
          
        h2 { 
            font-family: Impact; 
        } 
          
        body { 
            text-align: center; 
        } 
    </style> 
</head> 
  
<body> 
  
    <h1>GeeksforGeeks</h1> 
    <h2>Window atob() Method</h2> 
  
    <p> 
      For decoding a base-64 encoded string, 
      double click the "Decode Message" button: 
    </p> 
  
    <button ondblclick="decode()"> 
      Decode Message 
    </button> 
  
    <p id="myDecoding"></p> 
  
    <script> 
        function decode() { 
            var original = "GeeksforGeeks"; 
            var encoded = window.btoa(original); 
            var decoded = window.atob(encoded); 
  
            var output = "Encoded String : "  
            + encoded + "<br>" + "Decoded String : " 
            + decoded; 
            document.getElementById("myDecoding").innerHTML = 
              output; 
        } 
    </script> 
  
</body> 
  
</html> 