Не отображается id элемента, но id задан

var playBtn1 = document.getElementById('play1');
var myAudio1 = document.getElementById("myAudio1");
var isPlaying = false;
$(playBtn1).click(function() {
  if (isPlaying) {
    myAudio1.pause()
  } else {
    myAudio1.play();
  }
});

myAudio1.onplaying = function() {
  isPlaying = true;
  $(playBtn1).removeClass('ion-play1');
  $(playBtn1).addClass('ion-pause1');
};
myAudio1.onpause = function() {
  isPlaying = false;
  $(playBtn1).addClass('ion-play1');
  $(playBtn1).removeClass('ion-pause1');
};



var playBtn2 = document.getElementById('play2');
var myAudio2 = document.getElementById("myAudio2");
var isPlaying = false;
$(playBtn2).click(function() {
  if (isPlaying) {
    myAudio2.pause()
  } else {
    myAudio2.play();
  }
});

myAudio2.onplaying = function() {
  isPlaying = true;
  $(playBtn2).removeClass('ion-play2');
  $(playBtn2).addClass('ion-pause2');
};
myAudio2.onpause = function() {
  isPlaying = false;
  $(playBtn2).addClass('ion-play2');
  $(playBtn2).removeClass('ion-pause2');
};



var playBtn3 = document.getElementById('play3');
var myAudio3 = document.getElementById("myAudio3");
var isPlaying = false;
$(playBtn3).click(function() {
  if (isPlaying) {
    myAudio3.pause()
  } else {
    myAudio3.play();
  }
});

myAudio3.onplaying = function() {
  isPlaying = true;
  $(playBtn3).removeClass('ion-play3');
  $(playBtn3).addClass('ion-pause3');
};
myAudio3.onpause = function() {
  isPlaying = false;
  $(playBtn3).addClass('ion-play3');
  $(playBtn3).removeClass('ion-pause3');
};



var playBtn4 = document.getElementById('play4');
var myAudio4 = document.getElementById("myAudio4");
var isPlaying = false;
$(playBtn4).click(function() {
  if (isPlaying) {
    myAudio4.pause()
  } else {
    myAudio4.play();
  }
});

myAudio4.onplaying = function() {
  isPlaying = true;
  $(playBtn4).removeClass('ion-play4');
  $(playBtn4).addClass('ion-pause4');
};
myAudio4.onpause = function() {
  isPlaying = false;
  $(playBtn4).addClass('ion-play4');
  $(playBtn4).removeClass('ion-pause4');
};



var playBtn5 = document.getElementById('play5');
var myAudio5 = document.getElementById("myAudio5");
var isPlaying = false;
$(playBtn5).click(function() {
  if (isPlaying) {
    myAudio5.pause()
  } else {
    myAudio5.play();
  }
});

myAudio5.onplaying = function() {
  isPlaying = true;
  $(playBtn5).removeClass('ion-play5');
  $(playBtn5).addClass('ion-pause5');
};
myAudio5.onpause = function() {
  isPlaying = false;
  $(playBtn5).addClass('ion-play5');
  $(playBtn5).removeClass('ion-pause5');
};



var playBtn6 = document.getElementById('play6');
var myAudio6 = document.getElementById("myAudio6");
var isPlaying = false;
$(playBtn6).click(function() {
  if (isPlaying) {
    myAudio6.pause()
  } else {
    myAudio6.play();
  }
});

myAudio6.onplaying = function() {
  isPlaying = true;
  $(playBtn6).removeClass('ion-play6');
  $(playBtn6).addClass('ion-pause6');
};
myAudio6.onpause = function() {
  isPlaying = false;
  $(playBtn6).addClass('ion-play6');
  $(playBtn6).removeClass('ion-pause6');
};

<div class="img-slayder-audio">
  <img src="imgs/voice.svg" id="play1" class="ion-play1" />
  <img src="imgs/voice.svg" id="play2" class="ion-play2" />
  <img src="imgs/voice.svg" id="play3" class="ion-play3" />
  <img src="imgs/voice.svg" id="play4" class="ion-play4" />
  <img src="imgs/voice.svg" id="play5" class="ion-play5" />
  <img src="imgs/voice.svg" id="play6" class="ion-play6" />
</div>
<div>
  <audio id="myAudio1" src="01.mp3" preload="auto"></audio>
  <audio id="myAudio2" src="02.mp3" preload="auto"></audio>
  <audio id="myAudio3" src="03.mp3" preload="auto"></audio>
  <audio id="myAudio4" src="04.mp3" preload="auto"></audio>
  <audio id="myAudio5" src="05.mp3" preload="auto"></audio>
  <audio id="myAudio6" src="06.mp3" preload="auto"></audio>
</div>