为什么第n个子选择器不起作用？

Question

我正在使用

nth-child

选择器为不同的社交图标添加背景图像。然而，所有图标看起来都是一样的。我做错了什么？

.social-logo {
    display: inline-block;
    width: 24px;
    height: 24px;
    transition: background-image .2s;
}

#social-links div:nth-child(1) {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-linkedin.svg');
}

#social-links div:nth-child(1):hover {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-linkedin-copy.svg');
}

#social-links div:nth-child(2) {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-dribbble.svg');
}

#social-links div:nth-child(2):hover {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-dribbble-copy.svg');
}

#social-links div:nth-child(3) {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-email.svg');
}

#social-links div:nth-child(3):hover {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-email-copy.svg');
}

#social-links div:nth-child(4) {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-insta.svg');
}

#social-links div:nth-child(4):hover {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-insta-copy.svg');
}

<div id="social-links">
  <a href=""><div class="social-logo"></div></a>
  <a href=""><div class="social-logo"></div></a>
  <a href=""><div class="social-logo"></div></a>
  <a href=""><div class="social-logo"></div></a>
</div>

Answer 1

nth-child

选择器计算兄弟元素（即具有相同父元素的元素）。

在 HTML 结构中，

div.social-logo

始终是

a

的第一个、最后一个和唯一的子级。所以

nth-child

只有一个元素需要计数。

但是，有多个锚元素，所有这些元素都是同级元素（

#social-links

的子元素），因此

nth-child

可以定位每一个。

#social-links a:nth-child(1) div 
#social-links a:nth-child(2) div 
#social-links a:nth-child(3) div 
              .
              .
              .

Answer 2

在“:”之前添加空格 示例：-

tr :nth-child(2)
{
    text-align: right;
}

Answer 3

我想提一下，在我的例子中，当使用 React 和 node-sass 时，如果我只传递

nth-child

，则

1

属性不起作用，我需要指定

1n

才能使其工作。所以最终它的工作原理是：

.myClass {
  &:nth-child(1n)     { color: red; }
  &:nth-child(2n + 1) { color: blue; }
}

Answer 4

试试这个！

<div id="social-links">
  <a href=""><div class="social-logo"></div></a>
  <a href=""><div class="social-logo"></div></a>
  <a href=""><div class="social-logo"></div></a>
  <a href=""><div class="social-logo"></div></a>
</div>

CSS

.social-logo {
    display: inline-block;
    width: 24px;
    height: 24px;
    transition: background-image .2s;
}

#social-links a:nth-child(1) .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-linkedin.svg');
}

#social-links a:nth-child(1):hover .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-linkedin-copy.svg');
}

#social-links a:nth-child(2) .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-dribbble.svg');
}

#social-links a:nth-child(2):hover .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-dribbble-copy.svg');
}

#social-links a:nth-child(3) .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-email.svg');
}

#social-links a:nth-child(3):hover .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-email-copy.svg');
}

#social-links a:nth-child(4) .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-insta.svg');
}

#social-links a:nth-child(4):hover .social-logo {
    background-image: url('https://mysql-raigovind93.c9users.io/Cally%20Dai//img/footer/logo-insta-copy.svg');
}

现场演示 - https://jsfiddle.net/g59wa8uf/

Answer 5

在我的测试页面上，这是因为

<hr />

标签会破坏选择器逻辑的计数。