独家CSS选择器 [英] Exclusive CSS selector

问题描述

我正在一个页面上，其中列表中的所选项目的特征是没有给定的类.类似于以下内容:

I am working on a page where the selected item among a list is characterized by NOT having a given class. Something like the following:

<ul>
  <li class="a">not selected</li>
  <li class="a b">selected</li>
  <li class="a">not selected</li>
</ul>

我想定义一个CSS选择器来获取只有a类的页面中的li节点. 不足为奇的是，以下语句是不够的:

I would like to defined a CSS selector to grab the li node in the page having ONLY the a class. Unsurprisingly the following statement is not enough:

document.querySelectorAll('li.a')

因为它返回所有具有 a 类的 li 节点.

Because it returns ALL the li nodes having the a class.

在这种情况下有经验吗?

Any experience on such scenario?

推荐答案

在这种情况下，您可以考虑使用属性选择器，如下所示:

In such case you may consider attribute selector like this:

console.log(document.querySelectorAll('li[class="a"]').length)

li[class="a"] {
  color:red;
}

<ul>
  <li class="a">Select me</li>
  <li class="a b c d more classes">Don't select me</li>
  <li class="a b">Don't select me</li>
  <li class="a">Select me</li>
</ul>

只需注意多余的空格:

console.log(document.querySelectorAll('li[class="a"]').length)

li[class="a"] {
  color:red;
}

<ul>
  <li class="a ">Pay attention to this one !!</li>
  <li class="a b">Don't select me</li>
  <li class="a">Select me</li>
</ul>

但是由于您使用的是JS，因此可以使用

But since you are using JS you can use trim() to get rid of the extra spaces:

var elem=document.querySelectorAll('li');
for(var i=0;i<elem.length;i++)
  elem[i].className=elem[i].className.trim();

console.log(document.querySelectorAll('li[class="a"]').length)

li[class="a"] {
  color:red;
}

<ul>
  <li class="a ">Pay attention to this one !!</li>
  <li class="a b">Don't select me</li>
  <li class="a">Select me</li>
</ul>

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