freeCodeCamp/curriculum/challenges/chinese/01-responsive-web-design/basic-html-and-html5/check-radio-buttons-and-checkboxes-by-default.md

---
id: bad87fee1348bd9aedd08835
challengeType: 0
videoUrl: 'https://scrimba.com/p/pVMPUv/cWk3Qh6'
forumTopicId: 301094
title: 给单选按钮和复选框添加默认选中项
---

## Description
<section id='description'>
如果想设置某个单选按钮或多选按钮默认被选中，只需给<code>input</code>元素添加 "checked" 属性。 例如:
<code>&#60;input type="radio" name="test-name" checked&#62;</code>
</section>

## Instructions
<section id='instructions'>
把第一个<code>radio button</code>和第一个<code>checkbox</code>都设置为默认选中。
</section>

## Tests
<section id='tests'>

```yml
tests:
  - text: '表单的第一个单选按钮应该被默认选中。'
    testString: assert($('input[type="radio"]').prop("checked"));
  - text: '表单的第一个多选按钮应该被默认选中。'
    testString: assert($('input[type="checkbox"]').prop("checked"));

```

</section>

## Challenge Seed
<section id='challengeSeed'>

<div id='html-seed'>

```html
<h2>CatPhotoApp</h2>
<main>
<p>点击查看更多<a href="#">猫咪图片</a>。</p>
  
  <a href="#"><img src="https://bit.ly/fcc-relaxing-cat" alt="一只仰卧着的萌猫"></a>
  
  <p>猫咪最喜欢的三件东西：</p>
  <ul>
    <li>猫薄荷</li>
    <li>激光笔</li>
    <li>千层饼</li>
  </ul>
  <p>猫咪最讨厌的三件东西：</p>
  <ol>
    <li>跳蚤</li>
    <li>打雷</li>
    <li>同类</li>
  </ol>
  <form action="https://freecatphotoapp.com/submit-cat-photo">
    <label><input type="radio" name="indoor-outdoor">室内</label>
    <label><input type="radio" name="indoor-outdoor">室外</label><br>
    <label><input type="checkbox" name="personality">忠诚</label>
    <label><input type="checkbox" name="personality">懒惰</label>
    <label><input type="checkbox" name="personality">积极</label><br>
    <input type="text" placeholder="猫咪图片地址" required>
    <button type="submit">提交</button>
  </form>
</main>
```

</div>



</section>

## Solution
<section id='solution'>
</section>