Simple ROT13 Cypher for JS

gistfile1.js

var Decipher = function(text, rot){
	var lookup = ["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"];

    //clone the original lookup table to make a new one
	var newLookup = lookup.slice(0);
	//This is the offset to go off of
	var offset = rot;
	//split the message into characters to check against table but lowercase all chars first
	var msg = text.toLowerCase().split('');
    //New end of the lookup array
	var newEndLookup = newLookup.splice(0, offset);
	//put the new reordered lookup together for the comparison
	var newLookup = newLookup.concat(newEndLookup);
	//loop through the msg using lookup tables to find new chars and build array of them
	var decoded = [];
	msg.forEach(function(element, index){
		//Get the offset position of the character
		var pos = newLookup.indexOf(element);
		//Lookup the actual position in the character lookup table
		var newElement = lookup[pos];
		//If it isnt an empty space character
		if(pos !== -1){
			decoded.push(newElement);
		} else {
			decoded.push(" ");
		}
	});
	//Join the decoded array back into a string
	var decodedMsg = decoded.join('');
	console.log("Original Message: " + text);
	 console.log("The ROT Type: " + rot);
	 console.log("The Decoded Message: " + decodedMsg);
	return { 
		ogMsg: text, 
		rotType: rot,
		decodedMsg: decodedMsg
	 };

};