Java Script - Base64 Encoding/Decoding

// Create Base64 Object
var Base64={_keyStr:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",encode:function(e) {
 var t="";
 var n,r,i,s,o,u,a;
 var f=0;
 e=Base64._utf8_encode(e);
while(f<e.length){n=e.charCodeAt(f++);
r=e.charCodeAt(f++);
i=e.charCodeAt(f++);
s=n>>2;
o=(n&3)<<4|r>>4;
u=(r&15)<<2|i>>6;
a=i&63;
 if(isNaN(r)){u=a=64}
  else if(isNaN(i)){a=64}t=t+this._keyStr.charAt(s)+this._keyStr.charAt(o)+this._keyStr.charAt(u)+this._keyStr.charAt(a)}
 return t},decode:function(e){
var t="";
var n,r,i;
var s,o,u,a;
var f=0;
e=e.replace(/[^A-Za-z0-9\+\/\=]/g,"");
while(f<e.length {s=this._keyStr.indexOf(e.charAt(f++));
 o=this._keyStr.indexOf(e.charAt(f++));
 u=this._keyStr.indexOf(e.charAt(f++));
 a=this._keyStr.indexOf(e.charAt(f++));
 n=s<<2|o>>4;
 r=(o&15)<<4|u>>2;
 i=(u&3)<<6|a;
 t=t+String.fromCharCode(n);
if(u!=64){t=t+String.fromCharCode(r)}
if(a!=64){t=t+String.fromCharCode(i)}
 }t=Base64._utf8_decode(t);
return t},_utf8_encode:function(e){e=e.replace(/\r\n/g,"\n");
var t="";
for(var n=0; n<e.length; n++){
var r=e.charCodeAt(n);
if(r<128){
t+=String.fromCharCode(r)}else if(r>127&&r<2048){t+=String.fromCharCode(r>>6|192);
t+=String.fromCharCode(r&63|128)}
 else{t+=String.fromCharCode(r>>12|224);
t+=String.fromCharCode(r>>6&63|128);
t+=String.fromCharCode(r&63|128)}}return t},_utf8_decode:function(e){
var t="";
var n=0;
var r=c1=c2=0;
while(n<e.length){r=e.charCodeAt(n);
if(r<128){t+=String.fromCharCode(r);
n++}
 else if(r>191&&r<224){c2=e.charCodeAt(n+1);
t+=String.fromCharCode((r&31)<<6|c2&63);
n+=2}
 else{c2=e.charCodeAt(n+1);
c3=e.charCodeAt(n+2);
t+=String.fromCharCode((r&15)<<12|(c2&63)<<6|c3&63);
n+=3}}return t}} 

// Define the string
var string = 'Hello World!';

// Encode the String
var encodedString = Base64.encode(string);
console.log(encodedString); // Outputs: "SGVsbG8gV29ybGQh"

// Decode the String
var decodedString = Base64.decode(encodedString);
console.log(decodedString); // Outputs: "Hello World!"

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