Simplest way to obfuscate and deobfuscate a string in JavaScript

I'm looking for a way to obfuscate and deobfuscate a string in JavaScript; by which I mean encryption and decryption when security is not an issue. Ideally something native to JS (like base64_encode() and base64_decode() in PHP) to "turn a string into something else and back again" without having to write a function.

Any suggestions welcome!

You can use btoa() and atob(). btoa() is like base64_encode() and atob() like base64_decode().

Here is an example:

btoa('Some text'); // U29tZSB0ZXh0
atob('U29tZSB0ZXh0'); // Some text

Keep in mind that this is not a secure way to keep secrets. Base64 is a binary-to-text encoding scheme that represents binary data in an ASCII string format by translating it into a radix-64 representation.

It's worth noting that

evaluates to the string "fail" without ever looking like a string. Seriously, enter it into node and be amazed. You can spell anything in JavaScript by being crazy.

I'm obviously too late for an answer, but I was just working on another solution for the problem and base64 seemed to be to weak.

It works like this:

"abc;123!".obfs(13) // => "nopH>?@."
"nopH>?@.".defs(13) // => "abc;123!"

Code:

/**
 * Obfuscate a plaintext string with a simple rotation algorithm similar to
 * the rot13 cipher.
 * @param  {[type]} key rotation index between 0 and n
 * @param  {Number} n   maximum char that will be affected by the algorithm
 * @return {[type]}     obfuscated string
 */
String.prototype.obfs = function(key, n = 126) {
  // return String itself if the given parameters are invalid
  if (!(typeof(key) === 'number' && key % 1 === 0)
    || !(typeof(key) === 'number' && key % 1 === 0)) {
    return this.toString();
  }

  var chars = this.toString().split('');

  for (var i = 0; i < chars.length; i++) {
    var c = chars[i].charCodeAt(0);

    if (c <= n) {
      chars[i] = String.fromCharCode((chars[i].charCodeAt(0) + key) % n);
    }
  }

  return chars.join('');
};

/**
 * De-obfuscate an obfuscated string with the method above.
 * @param  {[type]} key rotation index between 0 and n
 * @param  {Number} n   same number that was used for obfuscation
 * @return {[type]}     plaintext string
 */
String.prototype.defs = function(key, n = 126) {
  // return String itself if the given parameters are invalid
  if (!(typeof(key) === 'number' && key % 1 === 0)
    || !(typeof(key) === 'number' && key % 1 === 0)) {
    return this.toString();
  }

  return this.toString().obfs(n - key);
};