function rot13(str) {
	// LBH QVQ VG!

	var newString = '';
	function charVal(char) {
		if (char < 65) {
			return char;
		} else {
			return char % 26 + 65;
		}
	}
	for (var i = 0; i < str.length; i++) {
		var x = str.charCodeAt(i);
		newString += String.fromCharCode(charVal(x));
	}
	return newString;
}

// Change the inputs below to test
//rot13("SERR PBQR PNZC")
//rot13("SERR CVMMN!")
//rot13("SERR YBIR?")
//rot13("GUR DHVPX OEBJA QBT WHZCRQ BIRE GUR YNML SBK.")
rot13('LBH QVQ VG!');