Keydown事件无法正常工作

我是javascript / jquery的新手，正在尝试运行以下代码：

function playSound(chosenColour) {

  var sound = new Audio("sounds/" + chosenColour + ".mp3");
  sound.play();
}

function nextInSequence() {
  var randomNumber = Math.floor(Math.random() * 4);
  var randomChosenColour = buttonColours[randomNumber];
  gamePattern.push(randomChosenColour);

  $("#" + randomChosenColour).animate({
    opacity: 0
  }, {
    duration: 50,
    start: function() {
      playSound(randomChosenColour);
    }
  }).animate({
    opacity: 1
  }, 50);
}

The nextInSequence() function is called via a keydown event listener. For some reason when I press the alt, ctrl, shift or windows keys, the animate part of the code runs but it doesn't playSound(). Can someone please explain why?