使用mousedown的Mouseover事件

Question

我需要你的帮助。有一个虚拟钢琴的应用程序。当我单击该键时，相关注释为reproduced.If the click is single，一切正常。但当我按住鼠标键并将光标放在按键上时，声音不会发出。可能的问题是什么？我想问题出在第15行的函数中，但我不知道如何解决它。请帮帮我。提前谢谢。这是JS代码

​

const piano = document.querySelector(".piano");
const collectionPiano = document.querySelectorAll(".piano-key");


function setActiveKey(event) { //active status keys mouse event
  event.target.classList.add("piano-key-active", "piano-key-active-pseudo");
}

function removeActiveKey(event) { //remove active status keys mouse event 
  event.target.classList.remove("piano-key-active", "piano-key-active-pseudo");
}

function playAudio (note) { //start function playAudio
  const audio = document.querySelector(`audio[data-note="${note}"]`);
  audio.currentTime = 0;
  audio.play();
}

function startKeyActive (event) { //mouseover and mouseout events for active status keys, pseudo and play audio
  if (event.target.classList.contains("piano-key")) {
    event.target.classList.add("piano-key-active", "piano-key-active-pseudo");
    const note = event.target.dataset.note;
    playAudio(note);
  }
  collectionPiano.forEach((el) => {
    // el.addEventListener("mouseover", playAudio);
    el.addEventListener("mouseover", setActiveKey);
    el.addEventListener("mouseout", removeActiveKey);
  });
};

function stopKeyIActive () { //remove mouseover and mouseout events for active status keys, pseudo and play audio
  collectionPiano.forEach((el) => {
    el.classList.remove("piano-key-active", "piano-key-active-pseudo");
    // el.removeEventListener("mouseover", playAudio);
    el.removeEventListener("mouseover", setActiveKey);
    el.removeEventListener("mouseout", removeActiveKey);
  });
};

piano.addEventListener("mousedown", startKeyActive);
piano.addEventListener("mousedown", playAudio);
document.addEventListener("mouseup", stopKeyIActive);


window.addEventListener("keydown", (event) => { // Event keyboard - play audio
  if (event.repeat) {
    return;
  } 
  const audioKeys = document.querySelector(`audio[data-key="${event.keyCode}"]`);
  const pianoKey = document.querySelector(`.piano-key[data-key="${event.keyCode}"]`);
  audioKeys.currentTime = 0;
  audioKeys.play(); 
  pianoKey.classList.add('piano-key-active');

  window.addEventListener("keyup", () => {
    pianoKey.classList.remove('piano-key-active');
  })
});

* {
    padding: 0;
    margin: 0;
    box-sizing: border-box;
    user-select: none;
}
a:focus {
    outline: 0;
}
html {
    background: #313940;
}
body {
    min-height: 100vh;
    background-color: #313940;
    font-family: "Open Sans", Arial, Helvetica, sans-serif;
    background: #313940;
    overflow-x: hidden;
}
.header {
    text-align: center;
    width: 100%;
    border-bottom: 1px solid;
    border-image-slice: 1;
    border-image-source: linear-gradient(to left, #38495a, #a2abb3, #38495a);
}
.header-title {
    line-height: 60px;
    font-weight: 300;
    color: #fff;
}
.main {
    min-height: calc(100vh - 110px);
    padding: 60px 10px 0;
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: space-between;
    width: 100%;
    max-width: 1140px;
    margin: 0 auto;
}
.btn-container {
    display: flex;
    justify-content: space-between;
    width: 306px;
    height: 40px;
    margin: 0 auto;
    margin-bottom: 80px;
}
.btn {
    width: 150px;
    height: 40px;
    padding: 0 10px;
    background-color: #454c53;
    border: 0;
    border-radius: 2px;
    font-family: "Open Sans", sans-serif;
    font-size: 16px;
    font-weight: 300;
    color: #fff;
    outline: 0;
    cursor: pointer;
    transition: 0.3s;
}
.btn:not(.btn-active):hover {
    background-color: #515961;
}
.btn:active {
    background-color: #00c9b7;
}
.btn-active {
    background-color: #00b4a4;
}
.btn-active:hover {
    background-color: #00c9b7;
}
.piano {
    position: relative;
    display: flex;
    justify-content: space-between;
    width: 100%;
    height: 270px;
    max-width: 560px;
    margin: 0 auto 60px;
}
.piano-key {
    position: relative;
    width: 80px;
    height: 270px;
    background-color: rgba(255, 255, 255, 0.85);
    border: 4px solid #313940;
    border-radius: 0px 0px 12px 12px;
    transition: 0.3s;
    cursor: pointer;
}
.piano-key:hover {
    background-color: #fff;
}
.keys-sharp {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 53px;
    right: 53px;
    display: flex;
    justify-content: space-between;
    pointer-events: none;
}
.piano-key.sharp {
    width: 54px;
    height: 170px;
    background-color: #313940;
    border: 0;
    border-radius: 0px 0px 9px 9px;
    top: 0;
    z-index: 3;
    pointer-events: auto;
    transform-origin: center top;
}
.piano-key.piano-key-active,
.piano-key.sharp.piano-key-active {
    transform: scale(0.96);
}
.piano-key.none {
    background-color: transparent;
    border: 0;
    border-radius: 0;
    pointer-events: none;
}
.piano-key::before,
.piano-key::after {
    content: attr(data-note);
    position: absolute;
    width: 40px;
    height: 40px;
    font-size: 26px;
    line-height: 40px;
    text-align: center;
    color: #a2abb3;
    bottom: -45px;
    left: 20px;
    transition: 0.3s;
    pointer-events: none;
}
.piano-key::after {
    display: none;
    content: attr(data-letter);
}
.piano-key:hover::before,
.piano-key:hover::after {
    color: #d7dfe6;
}

.sharp:active {
    border-top: 0;
}

.piano-key.sharp::before,
.piano-key.sharp::after {
    bottom: 175px;
    left: 7px;
}
.piano-key.letter::before {
    display: none;
}
.piano-key.letter::after {
    display: block;
}
.piano-key-letter::before {
    content: attr(data-letter);
}

.piano-key-remove-mouse:active::before {
    color: #a2abb3;
}

.piano-key-active-pseudo:hover::after,
.piano-key-active-pseudo:hover::before,
.piano-key-active::after,
.piano-key-active::before {
    color: #00b4a4;
}

.fullscreen {
    position: fixed;
    top: 120px;
    right: 40px;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.3);
    border: 0;
    outline: 0;
    background-size: contain;
    transition: 0.3s;
    cursor: pointer;
    background-image: url("assets/svg/fullscreen-open.svg");
}
.fullscreen:hover {
    background-color: rgba(255, 255, 255, 0.5);
}
:-webkit-full-screen .fullscreen {
    background-image: url("assets/svg/fullscreen-exit.svg");
}
.footer {
    border-top: 1px solid;
    border-image-slice: 1;
    border-image-source: linear-gradient(to left, #38495a, #a2abb3, #38495a);
}
.footer-container {
    padding: 0 15px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    max-width: 1140px;
    margin: 0 auto;
}
.github {
    display: block;
    width: 120px;
    height: 45px;
    padding-left: 45px;
    background-image: url("assets/svg/github.svg");
    background-size: 35px;
    background-repeat: no-repeat;
    background-position: left center;
    line-height: 45px;
    color: #cbd5de;
    font-size: 16px;
    font-family: "Open Sans", sans-serif;
    transition: 0.3s;
}
.github:hover {
    color: #fff;
}
.rss {
    display: block;
    position: relative;
    font-family: "Open Sans", sans-serif;
    width: 86px;
    height: 32px;
    background-image: url("assets/svg/rss.svg");
    background-size: contain;
    background-repeat: no-repeat;
    background-position: left center;
    padding-right: 111px;
}
.rss-year {
    position: absolute;
    bottom: 0;
    right: 0;
    font-size: 21px;
    letter-spacing: -2px;
    color: #cbd5de;
    line-height: 0.9;
    font-weight: bold;
    transition: 0.3s;
}
.rss:hover .rss-year {
    right: -5px;
    letter-spacing: 0;
}
@media (max-width: 768px) {
    .fullscreen {
        top: 10px;
        right: 20px;
        width: 40px;
        height: 40px;
    }
}
@media (max-width: 600px) {
    .main {
        padding-top: 40px;
    }
    .piano {
        width: 310px;
        height: 160px;
    }
    .piano-key {
        width: 44px;
        height: 160px;
        border-radius: 0px 0px 8px 8px;
        border: 2px solid #313940;
    }
    .keys-sharp {
        left: 26px;
        right: 26px;
    }
    .piano-key.sharp {
        width: 36px;
        height: 100px;
        border-radius: 0px 0px 6px 6px;
    }
    .piano-key::before,
    .piano-key::after {
        width: 30px;
        height: 30px;
        font-size: 22px;
        bottom: -35px;
        left: 7px;
        font-size: 22px;
    }
    .piano-key.sharp::before,
    .piano-key.sharp::after {
        bottom: 115px;
        left: 3px;
    }
    .btn-container {
        width: 244px;
        height: 40px;
        margin-bottom: 80px;
    }
    .btn {
        width: 120px;
        height: 40px;
    }
}

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <link href="assets/piano.ico" rel="shortcut icon">
  <link href="https://fonts.gstatic.com" rel="preconnect">
  <link
    href="https://fonts.googleapis.com/css2?family=Open+Sans+Condensed:wght@300&family=Open+Sans:wght@300;400;800&display=swap"
    rel="stylesheet">
  <link href="style.css" rel="stylesheet">
  <title>virtual-piano</title>
</head>

<body>
  <header class="header">
    <h1 class="header-title">Virtual Piano</h1>
  </header>
  <main class="main">

    <div class="btn-container">
      <button class="btn btn-notes btn-active">Notes</button>
      <button class="btn btn-letters">Letters</button>
    </div>
    <div class="piano">
      <div class="piano-key" data-key="68" data-letter="D" data-note="c"></div>
      <div class="piano-key" data-key="70" data-letter="F" data-note="d"></div>
      <div class="piano-key" data-key="71" data-letter="G" data-note="e"></div>
      <div class="piano-key" data-key="72" data-letter="H" data-note="f"></div>
      <div class="piano-key" data-key="74" data-letter="J" data-note="g"></div>
      <div class="piano-key" data-key="75" data-letter="K" data-note="a"></div>
      <div class="piano-key" data-key="76" data-letter="L" data-note="b"></div>
      <div class="keys-sharp">
        <div class="piano-key sharp" data-key="82" data-letter="R" data-note="c♯"></div>
        <div class="piano-key sharp" data-key="84" data-letter="T" data-note="d♯"></div>
        <div class="piano-key sharp none"></div>
        <div class="piano-key sharp" data-key="85" data-letter="U" data-note="f♯"></div>
        <div class="piano-key sharp" data-key="73" data-letter="I" data-note="g♯"></div>
        <div class="piano-key sharp" data-key="79" data-letter="O" data-note="a♯"></div>
      </div>
    </div>

    <audio data-key="75" data-note="a" src="assets/audio/a.mp3"></audio>
    <audio data-key="79" data-note="a♯" src="assets/audio/a♯.mp3"></audio>
    <audio data-key="76" data-note="b" src="assets/audio/b.mp3"></audio>
    <audio data-key="68" data-note="c" src="assets/audio/c.mp3"></audio>
    <audio data-key="82" data-note="c♯" src="assets/audio/c♯.mp3"></audio>
    <audio data-key="70" data-note="d" src="assets/audio/d.mp3"></audio>
    <audio data-key="84" data-note="d♯" src="assets/audio/d♯.mp3"></audio>
    <audio data-key="71" data-note="e" src="assets/audio/e.mp3"></audio>
    <audio data-key="72" data-note="f" src="assets/audio/f.mp3"></audio>
    <audio data-key="85" data-note="f♯" src="assets/audio/f♯.mp3"></audio>
    <audio data-key="74" data-note="g" src="assets/audio/g.mp3"></audio>
    <audio data-key="73" data-note="g♯" src="assets/audio/g♯.mp3"></audio>

    <button class="fullscreen openfullscreen"></button>
  </main>
  <footer class="footer">
    <div class="footer-container">
      <a class="github" href="#" target="_blank" rel="noopener noreferrer">github</a>
      <a class="rss" href="https://rs.school/js/" target="_blank" rel="noopener noreferrer">
        <span class="rss-year">'21</span>
      </a>
    </div>
  </footer>
  <script src="script.js"></script>
</body>

</html>

​

Answer 1

我做到了，这是最终的代码JS

​

const piano = document.querySelector(".piano");
const collectionPiano = document.querySelectorAll(".piano-key");


function playAudio (event) { //active status keys mouse event
  event.target.classList.add("piano-key-active", "piano-key-active-pseudo");
  const note = event.target.dataset.note;
  const audio = document.querySelector(`audio[data-note="${note}"]`);
  audio.currentTime = 0;
  audio.play();
}

function removeActiveKey(event) { //remove active status keys mouse event 
  event.target.classList.remove("piano-key-active", "piano-key-active-pseudo");
}

function startKeyActive (event) { //mouseover and mouseout events for active status keys, pseudo and play audio
  if (event.target.classList.contains("piano-key")) {
    event.target.classList.add("piano-key-active", "piano-key-active-pseudo");

 
  }
  collectionPiano.forEach((el) => {
    el.addEventListener("mouseover", playAudio);
    el.addEventListener("mouseout", removeActiveKey);
  });
};

function stopKeyIActive () { //remove mouseover and mouseout events for active status keys, pseudo and play audio
  collectionPiano.forEach((el) => {
    el.classList.remove("piano-key-active", "piano-key-active-pseudo");
    el.removeEventListener("mouseover", playAudio);
    el.removeEventListener("mouseout", removeActiveKey);
  });
};

piano.addEventListener("mousedown", startKeyActive);
piano.addEventListener("mousedown", playAudio);
document.addEventListener("mouseup", stopKeyIActive);

window.addEventListener("keydown", (event) => { // Event keyboard - play audio
  if (event.repeat) {
    return;
  } 
  const audioKeys = document.querySelector(`audio[data-key="${event.keyCode}"]`);
  const pianoKey = document.querySelector(`.piano-key[data-key="${event.keyCode}"]`);
  audioKeys.currentTime = 0;
  audioKeys.play(); 
  pianoKey.classList.add('piano-key-active');

  window.addEventListener("keyup", () => {
    pianoKey.classList.remove('piano-key-active');
  })
});

​