guess.html

<script>
  var random, result;
  var findDifference = function(answer, guess) {
    if (answer > guess) {
      return answer - guess;
    }
    else {
      return guess - answer;
    }
  }

  var guessingGame = function(answer) {
    var guess, difference;
    guess = prompt("What's my number?");
    difference = findDifference(answer, guess);

    if (parseInt(guess) === answer) {
      console.log("Dagnabit, they got me!");
      return "You win!";
    }
    else {
      return "Off by: " + difference;
    }
  }

  random = Math.floor(Math.random() * 10)
  for (tries = 1; tries < 4; tries++) {
    result = guessingGame(random)
    alert(result);
  }
</script>