Encode / Decode to base64 - Javascript js

/*
* Title -> JavaScript Base64 Encoder Decoder
* Author -> Paul Gration
* URL -> http://www.i-labs.org
* Email -> pmgration(at)i-labs.org
*/

function JavaScriptBase64()
{
var string;
var base64;

this.JavaScriptBase64 = function(string)
{
this.string = new String(string);
this.base64 = new Array('A','B','C','D','E','F','G','H',
'I','J','K','L','M','N','O','P',
'Q','R','S','T','U','V','W','X',
'Y','Z','a','b','c','d','e','f',
'g','h','i','j','k','l','m','n',
'o','p','q','r','s','t','u','v',
'w','x','y','z','0','1','2','3',
'4','5','6','7','8','9','*','/');
}

this.encode = function()
{
var binary = new String();
var result = new String();
for(i = 0; i < this.string.length; i++)
{
binary += String("00000000" + this.string.charCodeAt(i).toString(2)).substring(this.string.charCodeAt(i).toString(2).length);
}
for(i = 0; i < binary.length; i+=6)
{
var number = new Number();
var counter = new Number();
for(j = 0; j < binary.substring(i, i+6).length; j++)
{
for(k = 32; k >= 1; k-=(k/2))
{
if(binary.substring(i, i+6).charAt(counter++) == "1")
{
number += k;
}
}
}
result += this.base64[number];
}
return result;
}

this.decode = function()
{
var binary = new String();
var result = new String();
for(i = 0; i < this.string.length; i++)
{
for(j = 0; j < this.base64.length; j++)
{
if(this.string.charAt(i) == this.base64[j])
{
binary += String("000000" + j.toString(2)).substring(j.toString(2).length);
}
}
}
for(i = 0; i < binary.length; i+=8)
{
var number = new Number();
var counter = new Number();
for(j = 0; j < binary.substring(i, i+8).length; j++)
{
for(k = 128; k >= 1; k-=(k/2))
{
if(binary.substring(i, i+8).charAt(counter++) == "1")
{
number += k;
}
}
}
result += String.fromCharCode(number);
}
return result;
}
}
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