var keyStr = "ABCDEFGHIJKLMNOP" +
		     "QRSTUVWXYZabcdef" +
		     "ghijklmnopqrstuv" +
		     "wxyz0123456789+/" +
		     "=";

function encode64(input)
{
	var output = "";
	
	var chr1, chr2, chr3 = "";
	var enc1, enc2, enc3, enc4 = "";
	var i = 0;
	
	do
	{
		chr1 = input.charCodeAt(i++);
		chr2 = input.charCodeAt(i++);
		chr3 = input.charCodeAt(i++);
		
		enc1 = chr1 >> 2;
		enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
		enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
		enc4 = chr3 & 63;
		
		if(isNaN(chr2)) enc3 = enc4 = 64;
		else if(isNaN(chr3)) enc4 = 64;
		
		output = output + 
		keyStr.charAt(enc1) + 
		keyStr.charAt(enc2) + 
		keyStr.charAt(enc3) + 
		keyStr.charAt(enc4);
		chr1 = chr2 = chr3 = "";
		enc1 = enc2 = enc3 = enc4 = "";
	}
	while (i < input.length);
	
	return output;
}

function decode64(input)
{
	var output = "";
	var chr1, chr2, chr3 = "";
	var enc1, enc2, enc3, enc4 = "";
	var i = 0;
	
	// remove all characters that are not A-Z, a-z, 0-9, +, /, or =
	var base64test = /[^A-Za-z0-9\+\/\=]/g;
	if (base64test.exec(input))
	{
		alert("There were invalid base64 characters in the input text.\n" +
		"Valid base64 characters are A-Z, a-z, 0-9, '+', '/', and '='\n" +
		"Expect errors in decoding.");
	}
	input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
	
	do
	{
		enc1 = keyStr.indexOf(input.charAt(i++));
		enc2 = keyStr.indexOf(input.charAt(i++));
		enc3 = keyStr.indexOf(input.charAt(i++));
		enc4 = keyStr.indexOf(input.charAt(i++));
		
		chr1 = (enc1 << 2) | (enc2 >> 4);
		chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
		chr3 = ((enc3 & 3) << 6) | enc4;
		
		output = output + String.fromCharCode(chr1);
		
		if(enc3 != 64) output = output + String.fromCharCode(chr2);
		if(enc4 != 64) output = output + String.fromCharCode(chr3);
		
		chr1 = chr2 = chr3 = "";
		enc1 = enc2 = enc3 = enc4 = "";	
	}
	while (i < input.length);
	
	return output;
}