HTML | DOM Window btoa() Method

The Window btoa() method is used for encoding a string in base-64 format.
The characters used by the Window btoa() method to encode the string are “A-Z”, “a-z”, “0-9”, “+”, “/” and “=” .



Parameters Used:

  • String: It is a mandatory parameter which specifies the string to be encoded.

Below program illustrates the Window btoa() Method:

Encoding a string in base-64 format.





<!DOCTYPE html>
      Window btoa() Method in HTML
        h1 {
            color: green;
        h2 {
            font-family: Impact;
        body {
            text-align: center;
    <h2>Window btoa() Method</h2>
      For encoding a string in base-64 format,
      double click the "Encode Message" button:
    <button ondblclick="encode()">
      Encode Message
    <p id="myEncoding"></p>
        function encode() {
            var original = "GeeksforGeeks";
            var encoded = window.btoa(original);
            var output = "Encoded String : " + encoded;
            document.getElementById("myEncoding").innerHTML =
              "Original String: " + original + "<br>" + output;



After clicking the button

Supported Browsers: The browser supported by Window btoa( ) Method are listed below:

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

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