function caesarShift(str, amount) {

        var output = '';

        for (var i = 0; i < str.length; i ++) {

            // Getting current character
            var current = str[i];

            // Checking if it is a letter.
            if (current.match(/[a-z]/i)) {

                // Get its ASCII value
                var asciiValue = str.charCodeAt(i);

                // Encrypting uppercase letters
                if ((asciiValue >= 65) && (asciiValue <= 90))
                    current = String.fromCharCode((((asciiValue - 65) + parseInt(amount)) % 26) + 65);

                // Encrypting lowercase letters
                else if ((asciiValue >= 97) && (asciiValue <= 122)){
                   current = String.fromCharCode((((asciiValue - 97) + parseInt(amount)) % 26) + 97);

                }
            }

            // Appending everything
            output += current;

        }
            return output;

    };