我试图减少不透明度仅对选定的元素，但它添加到所有。我有一个关闭按钮，一旦单击它，我想减少整个父元素的不透明度。但是，所有具有相同类的父元素的不透明度都会降低。
(function() {
document.querySelectorAll(".close").forEach(function(close) {
close.addEventListener("click", function() {
var card = document.getElementsByClassName("card");
for (i = 0; i < card.length; i++) {
card[i].style.opacity = "0.3";
}
});
});
})
();
答案 0 :(得分：1)
您的主要问题是，当您应该在循环中设置事件处理程序时，您正在遍历事件处理程序中的所有按钮。
如果您已经有对close元素的引用，则不需要另一个循环将其绑定到其所在的相应card元素，则只需使用{{3} }，以获取与选择器匹配的最接近的祖先。
此外，.forEach()返回的节点列表上的所有浏览器都不支持.querySelectorAll()，因此您应始终将该节点列表转换为数组。
(function() {
// Get all the close buttons and convert to an Array
let closeButtons = Array.prototype.slice.call(document.querySelectorAll(".close"));
// Loop over the array
closeButtons.forEach(function(button) {
// Set up a click event handler on each button
button.addEventListener("click", function() {
// The handler just needs to find the closest ancestor .card to the
// current .close button that is being clicked (accessible via "this")
// and change its style. The style should be already set up in a class
this.closest(".card").classList.add("fade");
});
});
})();/* Default styling of "close" buttons is hidden */
.card a.close {
display:none;
}
/* When ancestor "card" is hovered, change display to shown */
.card:hover a.close{
display:block;
font-weight:bold;
}
/* Change the opacity of just the selected element */
.fade {
opacity:.5;
}
/* ******************************** */
/*! normalize.css v1.1.0 | MIT License | git.io/normalize */
figure {
margin: 0
}
a:link {
text-decoration: none !important;
}
* {
-webkit-box-sizing: border-box;
box-sizing: border-box;
-webkit-transition: all 1s ease;
transition: all 1s ease;
}
html {
font-size: 100%;
font-family: sans-serif;
height: 100%;
}
body {
min-height: 100%;
margin: 0;
padding: 0;
background: #f8f8f8;
}
#wrapper {
-webkit-box-sizing: border-box;
box-sizing: border-box;
margin: 0 auto;
padding: 20px;
max-width: 980px;
background: #fff;
-webkit-box-shadow: 0px 2px 1px -1px rgba(0, 0, 0, 0.2), 0px 1px 1px 0px rgba(0, 0, 0, 0.14), 0px 1px 3px 0px rgba(0, 0, 0, 0.12);
box-shadow: 0px 2px 1px -1px rgba(0, 0, 0, 0.2), 0px 1px 1px 0px rgba(0, 0, 0, 0.14), 0px 1px 3px 0px rgba(0, 0, 0, 0.12);
border-radius: 2px;
}
.clearfix {
overflow: auto;
}
.clearfix::after {
content: "";
clear: both;
display: table;
}
.headline {
padding: 0 10px;
}
.headline .promoted-stories {
font-weight: bold;
color: #404040;
}
.headline .taboola-link {
float: right;
}
.headline .taboola-link a {
font-weight: 300;
line-height: normal;
text-align: right;
color: #888888;
font-size: 11px;
}
.cards {
display: -webkit-box;
display: -ms-flexbox;
display: flex;
-ms-flex-wrap: wrap;
flex-wrap: wrap;
}
.card {
display: block;
min-height: 1px;
margin: 1%;
-webkit-box-flex: 0;
-ms-flex: 0 0 31.33333333%;
flex: 0 0 31.33333333%;
-webkit-box-shadow: 0px 0px 1px -2px rgba(0, 0, 0, 0.2), 0px 0px 2px 0px rgba(0, 0, 0, 0.14), 0px 0px 0px 0px rgba(0, 0, 0, 0.12);
box-shadow: 0px 0px 1px -2px rgba(0, 0, 0, 0.2), 0px 0px 2px 0px rgba(0, 0, 0, 0.14), 0px 0px 0px 0px rgba(0, 0, 0, 0.12);
-webkit-transition: all .25s;
transition: all .25s;
position: relative;
}
.card:hover {
-webkit-transform: translate(0, -2px);
transform: translate(0, -2px);
-webkit-box-shadow: 0px 1px 2px -1px rgba(0, 0, 0, 0.2), 0px 3px 10px 0px rgba(0, 0, 0, 0.14), 0px 1px 3px 0px rgba(0, 0, 0, 0.12);
box-shadow: 0px 1px 2px -1px rgba(0, 0, 0, 0.2), 0px 3px 10px 0px rgba(0, 0, 0, 0.14), 0px 1px 3px 0px rgba(0, 0, 0, 0.12);
}
.overlay {
position: absolute;
left: 0;
top: 0;
bottom: 0;
right: 0;
}
.card .thumbnail {
display: block;
height: 130px;
}
.card img {
height: 100%;
width: 100%;
border: none;
-o-object-fit: cover;
object-fit: cover;
-o-object-position: 50% 50%;
object-position: 50% 50%;
}
.card-content {
padding: 5px 10px 25px;
}
.card .card-content .card-title {
margin: 5px 0 0 0;
overflow: hidden;
color: #000;
font-weight: bold;
max-height: 72px;
font-size: .875rem;
line-height: 1.5rem;
text-decoration: none;
}
.card .card-content .category {
color: #999999;
font-size: 11.0px;
font-weight: bold;
text-decoration: none;
margin: 5px 0 0 0;
overflow: hidden;
max-height: 52px;
}
.close {
position: absolute;
right: 15px;
top: 5px;
}
.close:before,
.close:after {
position: absolute;
left: 0;
right: 0;
content: ' ';
height: 15px;
width: 2px;
background-color: #fff;
}
.close:before {
-webkit-transform: rotate(45deg);
transform: rotate(45deg);
}
.close:after {
-webkit-transform: rotate(-45deg);
transform: rotate(-45deg);
}<section id="wrapper">
<div class="headline clearfix">
<span class="promoted-stories">Promoted stories</span>
<span class="taboola-link"><a href="#">Sponsored Links by Taboola</a></span>
</div>
<div class="cards clearfix">
<article class="card">
<a class="overlay" href="#overlay-link"></a>
<figure class="thumbnail">
<img src="https://img.ohmymag.co.uk/headline/480/0f2af4ec6e8d3971480358d00e67e2e8117d994e.jpg" alt="3 Reasons Why You Haven't Found Your Match Yet">
<a href="#" class="close hidden"></a><!-- close hidden button -->
</figure>
<div class="card-content">
<h2 class="card-title">3 Reasons Why You Haven't Found Your Match Yet</h2>
<p class="category">Dating life</p>
</div><!-- .card-content -->
</article><!-- .card -->
<article class="card">
<a class="overlay" href="#overlay-link"></a>
<figure class="thumbnail">
<img src="https://img.ohmymag.co.uk/headline/480/0f2af4ec6e8d3971480358d00e67e2e8117d994e.jpg" alt="Harry And Meghan Announce Baby On The Way">
<a href="#" class="close hidden"></a><!-- close hidden button -->
</figure>
<div class="card-content">
<h2 class="card-title">Harry And Meghan Announce Baby On The Way</h2>
<p class="category">Royals</p>
</div><!-- .card-content -->
</article><!-- .card -->
<article class="card">
<a class="overlay" href="#overlay-link"></a>
<figure class="thumbnail">
<img src="https://img.ohmymag.co.uk/headline/480/0f2af4ec6e8d3971480358d00e67e2e8117d994e.jpg" alt="Things Get Seriously Real As RuPaul Cast Open Up">
<a href="#" class="close hidden"></a><!-- close hidden button -->
</figure>
<div class="card-content">
<h2 class="card-title">Things Get Seriously Real As RuPaul Cast Open Up</h2>
<p class="category">Celebrities</p>
</div><!-- .card-content -->
</article><!-- .card -->
<article class="card">
<a class="overlay" href="#overlay-link"></a>
<figure class="thumbnail">
<img src="https://img.ohmymag.co.uk/headline/480/0f2af4ec6e8d3971480358d00e67e2e8117d994e.jpg" alt="A Tiger Collapsed In A Russian Circus Mid-Show">
<a href="#" class="close hidden"></a><!-- close hidden button -->
</figure>
<div class="card-content">
<h2 class="card-title">A Tiger Collapsed In A Russian Circus Mid-Show</h2>
<p class="category">Circus</p>
</div><!-- .card-content -->
</article><!-- .card -->
<article class="card">
<a class="overlay" href="#overlay-link"></a>
<figure class="thumbnail">
<img src="https://img.ohmymag.co.uk/headline/480/0f2af4ec6e8d3971480358d00e67e2e8117d994e.jpg" alt="Engagement On The Cards For Jack And Dani">
<a href="#" class="close hidden"></a><!-- close hidden button -->
</figure>
<div class="card-content">
<h2 class="card-title">Engagement On The Cards For Jack And Dani</h2>
<p class="category">Dating life</p>
</div><!-- .card-content -->
</article><!-- .card -->
<article class="card">
<a class="overlay" href="#overlay-link"></a>
<figure class="thumbnail">
<img src="https://img.ohmymag.co.uk/headline/480/0f2af4ec6e8d3971480358d00e67e2e8117d994e.jpg" alt="Attwood Hits Back At Rumours Of Dani Dyer Fued">
<a href="#" class="close hidden"></a><!-- close hidden button -->
</figure>
<div class="card-content">
<h2 class="card-title">Attwood Hits Back At Rumours Of Dani Dyer Fued</h2>
<p class="category">Gossip</p>
</div><!-- .card-content -->
</article><!-- .card -->
</div>
</section>