Why doesn't my if statement working?

var questions = [
  ['Kolik je 2x2?', '4'],
  ['Kdo je prezident Bananove republiky?', 'zeman'],
  ['Ma zirafa ctyri nohy a dve hlavy?', 'ne']
];
var good = '<h1>Spravne odpovedi</h1>' + '<ol>';
var bad = '<h1>Spatne odpovedi</h1>' + '<ol>';
var window;
var answer;
var score = 0;

for ( i = 0; i < questions.length; i += 1) {
  window = prompt(questions[i][0]);
  answer = questions[i][1];
  if ( window === answer ) {
    good += '<li>' + questions[i][0] + '</li>';
    score += 1;
  } else {
    bad += '<li>' + questions[i][0] + '</li>';
  } 
}

good += '</ol>';
bad += '</ol>';

function print(rightQuestions, wrongQuestions) {
  document.write("tvoje score je: " + score);
  document.write(rightQuestions, wrongQuestions);
}

print(good, bad);