freeCodeCamp/curriculum/challenges/chinese/03-front-end-development-libraries/bootstrap/create-a-class-to-target-with-jquery-selectors.md

---
id: bad87fee1348bd9aec908852
title: 用 jQuery 选择器给目标元素的添加 class
challengeType: 0
forumTopicId: 16815
dashedName: create-a-class-to-target-with-jquery-selectors
---

# --description--

并不是所有 class 属性都需要有对应的 CSS 样式。 有时候我们设置 class 只是为了更方便地在 jQuery 中选中这些元素。

为每一个 `button` 元素添加 `target` class。

# --hints--

每一个 `button` 元素都应该设置 `target` class

```js
assert($('.target').length > 5);
```

# --seed--

## --seed-contents--

```html
<div class="container-fluid">
  <h3 class="text-primary text-center">jQuery Playground</h3>
  <div class="row">
    <div class="col-xs-6">
      <div class="well">
        <button class="btn btn-default"></button>
        <button class="btn btn-default"></button>
        <button class="btn btn-default"></button>
      </div>
    </div>
    <div class="col-xs-6">
      <div class="well">
        <button class="btn btn-default"></button>
        <button class="btn btn-default"></button>
        <button class="btn btn-default"></button>
      </div>
    </div>
  </div>
</div>
```

# --solutions--

```html
<div class="container-fluid">
  <h3 class="text-primary text-center">jQuery Playground</h3>
  <div class="row">
    <div class="col-xs-6">
      <div class="well">
        <button class="target btn btn-default"></button>
        <button class="target btn btn-default"></button>
        <button class="target btn btn-default"></button>
      </div>
    </div>
    <div class="col-xs-6">
      <div class="well">
        <button class="target btn btn-default"></button>
        <button class="target btn btn-default"></button>
        <button class="target btn btn-default"></button>
      </div>
    </div>
  </div>
</div>
```