将鼠标悬停在上面的图像上时，如何更改滑块的不透明度？

Question

所以我有一个播放音频的图像，并在单击时更改图像。我在图像下方还有一个音量滑块。我的问题是，当鼠标悬停在图像上时，如何让滑块淡入淡出？

当悬停在滑块本身而不是图像上时，会出现滑块。我尝试将不透明度设置为变量并通过 JavaScript 更改它，但这似乎没有任何作用。

    function CoffeeChange() {
    if (Coffee.src == "https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png") {
        Coffee.src = "https://static.wixstatic.com/media/38d0c2_37f01de3219a4804a3cb29f39e57b48c~mv2.png"; 
    } else {
        Coffee.src = "https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png";
    }}

    document.getElementById("Coffee").onclick = function() {
        CoffeeChange()
        var audio = document.getElementById("CoffeeAudio");
        if (audio.paused) audio.play();
        else audio.pause();
    };

    volume.addEventListener("mousemove", coffeeVolume);

    function coffeeVolume(){
        document.getElementById("CoffeeAudio").volume = document.getElementById("volume").value / 100;
    }

    .slidecontainer {
      width: 100%;
    }

    .slider {
      -webkit-appearance: none;
      width: 100px;
      height: 15px;
      border-radius: 5px;  
      background: #d3d3d3;
      outline: none;
      -webkit-transition: .2s;
      transition: opacity .2s;
      position: relative;
      top: 130px;
      opacity:0;
    }

    .slider:hover {
      opacity: 1;
    }

    .slider::-webkit-slider-thumb {
      -webkit-appearance: none;
      appearance: none;
      width: 25px;
      height: 25px;
      border-radius: 50%;
      background: #4CAF50;
      cursor: pointer;
    }

    .slider::-moz-range-thumb {
      width: 25px;
      height: 25px;
      border-radius: 50%;
      background: #4CAF50;
      cursor: pointer;
    }

    <meta name="viewport" content="width=device-width, initial-scale=1">
    <div class="slidecontainer">
      <input type="range" min="0" max="100" value="100" class="slider" id="volume">
    </div>
    <img id="Coffee" src="https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png"
    height="100" width="100">


    <audio id="CoffeeAudio" loop>
       <source src="//music.wixstatic.com/preview/38d0c2_02a2ea74abbc49a29ae7bdfabd1091d0-128.mp3" type="audio/wav" />
    </audio>

我已经添加了整个代码，以明确我是如何做我迄今为止所做的事情的，以防万一有任何事情可能会阻止它工作。

Answer 1

你需要颠倒代码中<img>和.slidecontainer的顺序：

<img id="Coffee" src="https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png" height="100" width="100">
<div class="slidecontainer">
  <input type="range" min="0" max="100" value="100" class="slider" id="volume">
</div>

...并使用它

.slidecontainer {
  opacity: 0;
  transition: opacity .3s cubic-bezier(.4, 0, .2, 1); /* optional: fade transition */
}
.slidecontainer:hover, #Coffe:hover + .slidecontainer {
  opacity: 1;
  z-index: 1; /* optional: if img and the slider overlap, you want the slider on top */
}

另外，如果.slidecontainer 尚未定位（有一个设置的position 值，而不是static），您需要给它position:relative。这涵盖了它们重叠的情况。

工作示例：

function CoffeeChange() {
  if (Coffee.src == "https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png") {
    Coffee.src = "https://static.wixstatic.com/media/38d0c2_37f01de3219a4804a3cb29f39e57b48c~mv2.png";
  } else {
    Coffee.src = "https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png";
  }
}

document.getElementById("Coffee").onclick = function() {
  CoffeeChange()
  var audio = document.getElementById("CoffeeAudio");
  if (audio.paused) audio.play();
  else audio.pause();
};

volume.addEventListener("mousemove", coffeeVolume);

function coffeeVolume() {
  document.getElementById("CoffeeAudio").volume = document.getElementById("volume").value / 100;
}

.slidecontainer {
  width: 100%;
}

.slider {
  -webkit-appearance: none;
  width: 100px;
  height: 15px;
  border-radius: 5px;
  background: #d3d3d3;
  outline: none;
  -webkit-transition: .2s;
  transition: opacity .2s;
  position: relative;
}

.slider:hover {
  opacity: 1;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 25px;
  height: 25px;
  border-radius: 50%;
  background: #4CAF50;
  cursor: pointer;
}

.slider::-moz-range-thumb {
  width: 25px;
  height: 25px;
  border-radius: 50%;
  background: #4CAF50;
  cursor: pointer;
}

.slidecontainer {
  opacity: 0;
  transition: opacity .3s cubic-bezier(.4, 0, .2, 1);
}

.slidecontainer:hover,
#Coffee:hover+.slidecontainer {
  opacity: 1;
}

<img id="Coffee" src="https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png" height="100" width="100">
<div class="slidecontainer">
  <input type="range" min="0" max="100" value="100" class="slider" id="volume">
</div>
<audio id="CoffeeAudio" loop>
   <source src="//music.wixstatic.com/preview/38d0c2_02a2ea74abbc49a29ae7bdfabd1091d0-128.mp3" type="audio/wav" />
</audio>

Answer 2

好吧，您可以做的一件事是将<img> 和 .slidecontainer 包装在一个 div 中，并将鼠标悬停在这个包装器上，就像

   <section id="CoffeeAndSlider" onmouseover="showSlider('unhide')"onmouseout="showSlider('hide')">
            <div class="slidecontainer">
              <input type="range" min="0" max="100" value="100" class="slider" id="volume">
            </div>

            <img id="Coffee" src="https://static.wixstatic.com/media/38d0c2_f65cba752ac3460da7a56896d1195284~mv2.png"
            height="100" width="100">
     </section>

showSlider 看起来像

function showSlider(flag){
 if(flag==='unhide'){
    document.getElementById('volume').classList.add("unhide");
 }
 else if(flag==='unhide'){
 document.getElementById('volume').classList.remove("unhide");
 }
}

最后将其添加到您的 css 并删除 .slider:hover

.unhide{
    opacity: 1;
}