freeCodeCamp/curriculum/challenges/chinese/01-responsive-web-design/basic-html-and-html5/use-html5-to-require-a-fiel...

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id title challengeType videoUrl forumTopicId dashedName
bad87fee1348bd9aedc08830 给表单添加一个必填字段 0 https://scrimba.com/p/pVMPUv/cMd4EcQ 18360 use-html5-to-require-a-field

--description--

当你设计表单时你可以指定某些字段为必填项required只有当用户填写了该字段后才可以提交表单。

如果你想把文本输入框设置为必填项,在 input 元素中加上 required 属性就可以了,例如:<input type="text" required>

--instructions--

请给 input 元素加上 required 属性,这样用户就必须先在输入框里填入内容,然后才可以提交表单。

然后尝试在不输入任何文本的情况下提交表单, 看看 HTML5 表单是如何通知你这个字段是必填的。

--hints--

input 元素应有 required 属性。

assert($('input').prop('required'));

--seed--

--seed-contents--

<h2>CatPhotoApp</h2>
<main>
  <p>Click here to view more <a href="#">cat photos</a>.</p>

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

  <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">
    <input type="text" placeholder="cat photo URL">
    <button type="submit">Submit</button>
  </form>
</main>

--solutions--

<h2>CatPhotoApp</h2>
<main>
  <p>Click here to view more <a href="#">cat photos</a>.</p>

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

  <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">
    <input type="text" required placeholder="cat photo URL">
    <button type="submit">Submit</button>
  </form>
</main>