CSS z-index 属性和 javascript 背景鼠标交互

Question

我正在尝试添加一个径向渐变作为我的博文卡片的背景。 当 博客明信片悬停。这里我的小代码示例关于 效果（https://codepen.io/D_s/pen/OJNpNBV）。

问题在于它不能按预期工作，因为卡片的其他 div 元素（标题、图像、标签、按钮）正在干扰悬停。我怎么能解决这个问题？ 以下是博文卡片的代码：

let backgroundgradient = document.querySelector('.card');
backgroundgradient.onmousemove = function(e) {
let rect = e.target.getBoundingClientRect();
let x = e.clientX - rect.left;
let y = e.clientY - rect.top;
backgroundgradient.style.setProperty('--x', x + 'px');
backgroundgradient.style.setProperty('--y', y + 'px');
}

感谢您的帮助！

Answer 1

考虑使用.card 元素本身的.offsetLeft/.offsetRight，而不是使用e.target.getBoundingClientRect() 和.left/.right，它们会随着子元素的悬停而改变。

let backgroundgradient = document.querySelector('.card');
backgroundgradient.onmousemove = function(e) {
  let x = e.clientX - backgroundgradient.offsetLeft;
  let y = e.clientY - (backgroundgradient.offsetTop - window.pageYOffset);
  backgroundgradient.style.setProperty('--x', x + 'px');
  backgroundgradient.style.setProperty('--y', y + 'px');
}

.card,
.imagebox {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
}

.imagebox {
  flex: 3 1 30ch;
  height: calc(282px + 5vw);
  overflow: hidden;
}

.imagebox img {
  max-width: 100%;
  min-width: 100%;
  min-height: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: cover;
  object-position: 50% 50%;
  padding: 15px;
  border-radius: 30px;
  z-index: 1;
}

.card {
  background: #bdbdbd;
  box-sizing: border-box;
  border: 2px solid #f93668;
  overflow: hidden;
  position: relative;
  border-radius: 20px;
  overflow: hidden;
}

.card:before {
  --size: 0;
  content: '';
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: var(--size);
  height: var(--size);
  background: radial-gradient(circle closest-side, #f93668, transparent);
  transform: translate(-50%, -50%);
  transition: width 0.8s ease, height 0.4s ease;
}

.card:hover:before {
  --size: 90rem;
}

.card-content {
  padding: 16px 32px;
  flex: 10 1 40ch;
  z-index: 2;
}

.card-tags {
  margin: 0 -8px;
}

.card-tag {
  display: inline-block;
  margin: 8px;
  font-size: 0.875em;
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--primary);
}

.card-title {
  margin: 0;
  font-size: clamp(2.4em, 1.1vw, 1.1em);
  font-family: "Roboto Slab", Helvetica, Arial, sans-serif;
}

.card-title a {
  text-decoration: none;
  color: inherit;
}

.card-metadata {
  margin: 0;
}

.card-save {
  display: flex;
  align-items: center;
  padding: 6px 14px 6px 12px;
  border-radius: 4px;
  border: 2px solid currentColor;
  color: var(--primary);
  background: none;
  cursor: pointer;
  font-weight: bold;
}

.card-save svg {
  margin-right: 6px;
}


/* Body Layout */

* {
  box-sizing: border-box;
}

body {
  --primary: rgb(249, 54, 104);
  --grey: #454545;
  --lightgrey: #666;
  color: var(--grey);
  line-height: 1.55;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  font-family: "Roboto", Helvetica, Arial, sans-serif;
}

.container {
  width: clamp(20px, 90%, 90%);
  padding: 24px;
}

<div class="container">
  <article class="card">
    <div class="imagebox">
      <img src="https://d2w9rnfcy7mm78.cloudfront.net/2548871/original_eb4afb32258fcb72de6dddd99cbc4171.jpg?1534159969?bc=1" width="1500" height="1368" alt="">
    </div>
    <div class="card-content">
      <p class="card-tags">
        <span class="card-tag">Gluten Free</span>
        <span class="card-tag">Main dish</span>
      </p>
      <h1 class="card-title"><a href="#">Title for a post to come</a></h1>

      <p class="card-desc">by Slutty Urbanism</p>

      <button class="card-save" type="button">
                Read more
            </button>

    </div>
  </article>

</div>

具有多个卡片元素的示例...

let cards = document.querySelectorAll('.card');

for (let card of cards) {
  card.onmousemove = function(e) {
    let x = e.clientX - card.offsetLeft;
    let y = e.clientY - (card.offsetTop - window.pageYOffset);
    card.style.setProperty('--x', x + 'px');
    card.style.setProperty('--y', y + 'px');
  }
}

.card,
.imagebox {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
}

.imagebox {
  flex: 3 1 30ch;
  height: calc(282px + 5vw);
  overflow: hidden;
}
.imagebox img {
  max-width: 100%;
  min-width: 100%;
  min-height: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: cover;
  object-position: 50% 50%;
  padding: 15px;
  border-radius: 30px;
  z-index: 1;
}

.card {
  background: #bdbdbd;
  box-sizing: border-box;
  border: 2px solid #f93668;
  overflow: hidden;
  position: relative;
  border-radius: 20px;
  overflow: hidden;
}

.card:before {
  --size: 0;
  content: '';
  position: absolute;
  left: var(--x);
  top: var(--y);
  width: var(--size);
  height: var(--size);
  background: radial-gradient(circle closest-side, #f93668, transparent);
  transform: translate(-50%, -50%);
  transition: width 0.8s ease, height 0.4s ease;
}

.card:hover:before {
  --size: 90rem;
}

.card-content {
  padding: 16px 32px;
  flex: 10 1 40ch;
  z-index: 2;
}
.card-tags {
  margin: 0 -8px;
}
.card-tag {
  display: inline-block;
  margin: 8px;
  font-size: 0.875em;
  text-transform: uppercase;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--primary);
}
.card-title {
  margin: 0;
  font-size: clamp(2.4em, 1.1vw, 1.1em);
  font-family: "Roboto Slab", Helvetica, Arial, sans-serif;
}
.card-title a {
  text-decoration: none;
  color: inherit;
}
.card-metadata {
  margin: 0;
}
.card-save {
  display: flex;
  align-items: center;
  padding: 6px 14px 6px 12px;
  border-radius: 4px;
  border: 2px solid currentColor;
  color: var(--primary);
  background: none;
  cursor: pointer;
  font-weight: bold;
}
.card-save svg {
  margin-right: 6px;
}

/* Body Layout */
* {
  box-sizing: border-box;
}

body {
  --primary: rgb(249, 54, 104);
  --grey: #454545;
  --lightgrey: #666;
  color: var(--grey);
  line-height: 1.55;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  font-family: "Roboto", Helvetica, Arial, sans-serif;
}

.container {
  width: clamp(20px, 90%, 90%);
  padding: 24px;
}

<div class="container">
  <article class="card">
    <div class="imagebox">
      <img src="https://d2w9rnfcy7mm78.cloudfront.net/2548871/original_eb4afb32258fcb72de6dddd99cbc4171.jpg?1534159969?bc=1" width="1500" height="1368" alt="">
    </div>
    <div class="card-content">
      <p class="card-tags">
        <span class="card-tag">Gluten Free</span>
        <span class="card-tag">Main dish</span>
      </p>
      <h1 class="card-title"><a href="#">Title for a post to come</a></h1>

      <p class="card-desc">by Slutty Urbanism</p>

      <button class="card-save" type="button">
        Read more
      </button>

    </div>
  </article>

  <article class="card">
    <div class="imagebox">
      <img src="https://d2w9rnfcy7mm78.cloudfront.net/2548871/original_eb4afb32258fcb72de6dddd99cbc4171.jpg?1534159969?bc=1" width="1500" height="1368" alt="">
    </div>
    <div class="card-content">
      <p class="card-tags">
        <span class="card-tag">Gluten Free</span>
        <span class="card-tag">Main dish</span>
      </p>
      <h1 class="card-title"><a href="#">Title for a post to come</a></h1>

      <p class="card-desc">by Slutty Urbanism</p>

      <button class="card-save" type="button">
        Read more
      </button>

    </div>
  </article>

</div>