fix to battleship, adding back in firstChar with var declaration

Author: bethrobson

chapter8/battleship.js

@@ -147,7 +147,8 @@ function parseGuess(guess) {
 	if (guess === null || guess.length !== 2) {
 		alert("Oops, please enter a letter and a number on the board.");
 	} else {
-		var row = alphabet.indexOf(guess.charAt(0));
+		var firstChar = guess.charAt(0);
+		var row = alphabet.indexOf(firstChar);
 		var column = guess.charAt(1);
 
 		if (isNaN(row) || isNaN(column)) {