---
id: bad87fee1348cd8acef08812
title: 创建一个 Bootstrap 块级元素按钮
challengeType: 0
forumTopicId: 16810
dashedName: create-a-block-element-bootstrap-button
---

# --description--

一般情况下，`btn` 和 `btn-default` 两个 classes 修饰的 `button` 元素宽度与它包含的文本相同， 举个例子：

`<button class="btn btn-default">Submit</button>`

这个按钮的宽度应该和文本`Submit` 的宽度相同。

<button class='btn btn-default'>提交</button>

通过为按钮添加 class 属性 `btn-block` 使其成为块级元素，按钮会伸展并填满页面整个水平空间，后续的元素会流到这个块级元素的下方，即 "另起一行"。

`<button class="btn btn-default btn-block">Submit</button>`

这个按钮会 100% 占满所有的可用宽度。

<button class='btn btn-default btn-block'>提交</button>

记住这些按钮仍然需要 `btn` 这个 class。

添加 Bootstrap 的 `btn-block` class 到刚创建的 Bootstrap 按钮上吧。

# --hints--

按钮的 class 属性应该仍然包含 `btn` 和 `btn-default`。

```js
assert($('button').hasClass('btn') && $('button').hasClass('btn-default'));
```

按钮的 class 属性应该包含 `btn-block`。

```js
assert($('button').hasClass('btn-block'));
```

确保所有的 `button` 元素都有一个闭合标签。

```js
assert(
  code.match(/<\/button>/g) &&
    code.match(/<button/g) &&
    code.match(/<\/button>/g).length === code.match(/<button/g).length
);
```

# --seed--

## --seed-contents--

```html
<link href="https://fonts.googleapis.com/css?family=Lobster" rel="stylesheet" type="text/css">
<style>
  .red-text {
    color: red;
  }

  h2 {
    font-family: Lobster, Monospace;
  }

  p {
    font-size: 16px;
    font-family: Monospace;
  }

  .thick-green-border {
    border-color: green;
    border-width: 10px;
    border-style: solid;
    border-radius: 50%;
  }

  .smaller-image {
    width: 100px;
  }
</style>

<div class="container-fluid">
  <h2 class="red-text text-center">CatPhotoApp</h2>

  <p>Click here for <a href="#">cat photos</a>.</p>

  <a href="#"><img class="smaller-image thick-green-border" src="https://bit.ly/fcc-relaxing-cat" alt="A cute orange cat lying on its back."></a>

  <img src="https://bit.ly/fcc-running-cats" class="img-responsive" alt="Three kittens running towards the camera.">
  <button class="btn btn-default">Like</button>
  <p>Things cats love:</p>
  <ul>
    <li>cat nip</li>
    <li>laser pointers</li>
    <li>lasagna</li>
  </ul>
  <p>Top 3 things cats hate:</p>
  <ol>
    <li>flea treatment</li>
    <li>thunder</li>
    <li>other cats</li>
  </ol>
  <form action="https://freecatphotoapp.com/submit-cat-photo">
    <label><input type="radio" name="indoor-outdoor"> Indoor</label>
    <label><input type="radio" name="indoor-outdoor"> Outdoor</label>
    <label><input type="checkbox" name="personality"> Loving</label>
    <label><input type="checkbox" name="personality"> Lazy</label>
    <label><input type="checkbox" name="personality"> Crazy</label>
    <input type="text" placeholder="cat photo URL" required>
    <button type="submit">Submit</button>
  </form>
</div>
```

# --solutions--

```html
<link href="https://fonts.googleapis.com/css?family=Lobster" rel="stylesheet" type="text/css">
<style>
  .red-text {
    color: red;
  }

  h2 {
    font-family: Lobster, Monospace;
  }

  p {
    font-size: 16px;
    font-family: Monospace;
  }

  .thick-green-border {
    border-color: green;
    border-width: 10px;
    border-style: solid;
    border-radius: 50%;
  }

  .smaller-image {
    width: 100px;
  }
</style>

<div class="container-fluid">
  <h2 class="red-text text-center">CatPhotoApp</h2>

  <p>Click here for <a href="#">cat photos</a>.</p>

  <a href="#"><img class="smaller-image thick-green-border" src="https://bit.ly/fcc-relaxing-cat" alt="A cute orange cat lying on its back."></a>

  <img src="https://bit.ly/fcc-running-cats" class="img-responsive" alt="Three kittens running towards the camera.">
  <button class="btn btn-block btn-default">Like</button>
  <p>Things cats love:</p>
  <ul>
    <li>cat nip</li>
    <li>laser pointers</li>
    <li>lasagna</li>
  </ul>
  <p>Top 3 things cats hate:</p>
  <ol>
    <li>flea treatment</li>
    <li>thunder</li>
    <li>other cats</li>
  </ol>
  <form action="https://freecatphotoapp.com/submit-cat-photo">
    <label><input type="radio" name="indoor-outdoor"> Indoor</label>
    <label><input type="radio" name="indoor-outdoor"> Outdoor</label>
    <label><input type="checkbox" name="personality"> Loving</label>
    <label><input type="checkbox" name="personality"> Lazy</label>
    <label><input type="checkbox" name="personality"> Crazy</label>
    <input type="text" placeholder="cat photo URL" required>
    <button type="submit">Submit</button>
  </form>
</div>
```