向每个第二个元素添加类，从第一个元素开始计数

I have a list where I want to add classes to every second element, counting from the first one.

我有一个列表，我想在每个第二个元素中添加类，从第一个元素开始。

Here's my list

这是我的列表

<ul class="timeline">
  <span class="topbullet"></span>
  <li></li>
  <li></li>
  <div class="clearfix"></div>
  <li></li>
  <li></li>
  <div class="clearfix"></div>
  <li></li>
  <li></li>
  <div class="clearfix"></div>
  <li></li>
  <li></li>
  <div class="clearfix"></div>
  <li></li>
  <li></li>
  <div class="clearfix"></div>
</ul>

I want to have it like this:

我想这样:

<ul class="timeline">
  <span class="topbullet"></span>
  <li class="odd"></li>
  <li class="even"></li>
  <div class="clearfix"></div>
  <li class="odd"></li>
  <li class="even"></li>
  <div class="clearfix"></div>
  <li class="odd"></li>
  <li class="even"></li>
  <div class="clearfix"></div>
  <li class="odd"></li>
  <li class="even"></li>
  <div class="clearfix"></div>
  <li class="odd"></li>
  <li class="even"></li>
  <div class="clearfix"></div>
</ul>

Here's my jQuery Code

这是我的jQuery代码

$(".timeline li:nth-of-type(2n)").addClass('even');

It's no problem to add the 'even' classes, but how to add the 'odd' classes? Which selector should I use to count from the first list element?

添加“偶数”类没有问题，但是如何添加“奇数”类呢?我应该使用哪个选择器从第一个列表元素中计数?

7 个解决方案

#1

You can use odd and even selector of jquery like this

可以像这样使用奇数和偶数jquery选择器

$( ".timeline li:odd" ).addClass('odd');
$( ".timeline li:even" ).addClass('even');

For your requirement you need to first odd and than even so you change this jquery like this

对于您的需求，您需要首先对奇数进行修改，甚至可以这样修改这个jquery

$( ".timeline li:odd" ).addClass('even');
$( ".timeline li:even" ).addClass('odd');

#2

Or JUST this

还是这

document.body.querySelectorAll(".timeline li").forEach(function(node,i){
   node.classList.add(i % 2?"even":"odd");
})

#3

Just simply add prev() method to your code:

只需在代码中添加prev()方法:

$(".timeline li:nth-of-type(2n)").addClass('even').prev().addClass('odd');

.even{
  color:red;
}
.odd{
  color: orange;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul class="timeline">
  <span class="topbullet">Span</span>
  <li>Li</li>
  <li>Li</li>
  <div class="clearfix">Div</div>
  <li>Li</li>
  <li>Li</li>
  <div class="clearfix">Div</div>
  <li>Li</li>
  <li>Li</li>
  <div class="clearfix">Div</div>
  <li>Li</li>
  <li>Li</li>
  <div class="clearfix">Div</div>
  <li>Li</li>
  <li>Li</li>
  <div class="clearfix">Div</div>
</ul>

#4

You could do this:
Iterate through the elements matching ".timeline li" and add the correct class whether its index is even or not.

您可以这样做:遍历元素匹配”。并添加正确的类，无论其索引是否为偶数。

$(".timeline li").each((index, el) => $(el).addClass(index % 2 ? 'even' : 'odd'));

#5

Change:

变化:

$(".timeline li:nth-of-type(2n)").addClass('even');

to:

    $(".timeline li:nth-child(even)").addClass('even');

#6

If you just want to style elements you can target them using css

如果您只是想对元素进行样式化，您可以使用css对它们进行目标化

.timeline li:nth-of-type(2n + 1) {
    background: red;
}
.timeline li:nth-of-type(2n) {
    background: blue;
}

#7

You can add odd/even class like the below example.

$(document).ready(function() {
  $('ul.listul li:even').addClass('even');
  $('ul.listul li:odd').addClass('odd');
});

li.even {
  color: #000;
}

li.odd {
  color: red;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<ul class="listul">
  <li>list1</li>
  <li>list2</li>
  <li>list3</li>
  <li>list4</li>
  <li>list5</li>
  <li>list6</li>
</ul>

#1