How do I read a variable of a JSON array?

Question

I was just wondering if you could read a JSON array using a variable. My code:

var runningtotal = 0;
var dollartoletter = {
  "a": 1,
  "b": 2,
  "c": 3,
  "d": 4,
  "e": 5,
  "f": 6,
  "g": 7,
  "h": 8,
  "i": 9,
  "j": 10,
  "k": 11,
  "l": 12,
  "m": 13,
  "n": 14,
  "o": 15,
  "p": 16,
  "q": 17,
  "r": 18,
  "s": 19,
  "t": 20,
  "u": 21,
  "v": 22,
  "w": 23,
  "x": 24,
  "y": 25,
  "z": 26
};

for (var i = 0; i < word.length; i++) {
  var currentChar = word.charAt(i);
  console.log(currentChar);
  var numforcurrentChar = dollartoletter.currentChar; 
  // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^this is what produces errors
  console.log(numforcurrentChar);
  var runningtotal = runningtotal + numforcurrentChar;
  console.log(runningtotal);
}

If this is not possible, that's OK too. I would prefer not to use jQuery, but I'm fine with implementing it if it is required.