117 lines
3.6 KiB
Markdown
117 lines
3.6 KiB
Markdown
---
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id: bad87fee1348bd9aedd08835
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title: 给单选按钮和复选框添加默认选中项
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challengeType: 0
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videoUrl: 'https://scrimba.com/p/pVMPUv/cWk3Qh6'
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forumTopicId: 301094
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dashedName: check-radio-buttons-and-checkboxes-by-default
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---
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# --description--
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用 `checked` 属性把第一个复选框和单选按钮都设置为默认选中。
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为此，只需将单词 `checked` 添加到 `input` 元素的内部。 例如:
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```html
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<input type="radio" name="test-name" checked>
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```
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# --instructions--
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把第一个单选按钮和第一个复选框都设置为默认选中。
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# --hints--
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表单的第一个单选按钮应被默认选中。
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```js
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assert($('input[type="radio"]').prop('checked'));
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```
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表单的第一个复选框应被默认选中。
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```js
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assert($('input[type="checkbox"]').prop('checked'));
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```
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不应该更改 `Indoor` 标签的内部文本。
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```js
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assert.equal(document.querySelector('label[for="indoor"]')?.innerText?.trim(), 'Indoor');
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```
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不应该更改 `Loving` 标签的内部文本。
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```js
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assert.equal(document.querySelector('label[for="loving"]')?.innerText?.trim(), 'Loving');
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```
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# --seed--
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## --seed-contents--
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```html
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<h2>CatPhotoApp</h2>
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<main>
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<p>Click here to view more <a href="#">cat photos</a>.</p>
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<a href="#"><img src="https://cdn.freecodecamp.org/curriculum/cat-photo-app/relaxing-cat.jpg" alt="A cute orange cat lying on its back."></a>
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<p>Things cats love:</p>
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<ul>
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<li>cat nip</li>
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<li>laser pointers</li>
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<li>lasagna</li>
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</ul>
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<p>Top 3 things cats hate:</p>
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<ol>
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<li>flea treatment</li>
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<li>thunder</li>
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<li>other cats</li>
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</ol>
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<form action="https://www.freecatphotoapp.com/submit-cat-photo">
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<label for="indoor"><input id="indoor" type="radio" name="indoor-outdoor" value="indoor"> Indoor</label>
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<label for="outdoor"><input id="outdoor" type="radio" name="indoor-outdoor" value="outdoor"> Outdoor</label><br>
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<label for="loving"><input id="loving" type="checkbox" name="personality" value="loving"> Loving</label>
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<label for="lazy"><input id="lazy" type="checkbox" name="personality" value="lazy"> Lazy</label>
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<label for="energetic"><input id="energetic" type="checkbox" name="personality" value="energetic"> Energetic</label><br>
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<input type="text" placeholder="cat photo URL" required>
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<button type="submit">Submit</button>
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</form>
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</main>
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```
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# --solutions--
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```html
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<h2>CatPhotoApp</h2>
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<main>
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<p>Click here to view more <a href="#">cat photos</a>.</p>
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<a href="#"><img src="https://cdn.freecodecamp.org/curriculum/cat-photo-app/relaxing-cat.jpg" alt="A cute orange cat lying on its back."></a>
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<p>Things cats love:</p>
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<ul>
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<li>cat nip</li>
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<li>laser pointers</li>
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<li>lasagna</li>
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</ul>
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<p>Top 3 things cats hate:</p>
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<ol>
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<li>flea treatment</li>
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<li>thunder</li>
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<li>other cats</li>
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</ol>
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<form action="https://www.freecatphotoapp.com/submit-cat-photo">
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<label for="indoor"><input id="indoor" type="radio" name="indoor-outdoor" value="indoor" checked> Indoor</label>
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<label for="outdoor"><input id="outdoor" type="radio" name="indoor-outdoor" value="outdoor"> Outdoor</label><br>
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<label for="loving"><input id="loving" type="checkbox" name="personality" value="loving" checked> Loving</label>
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<label for="lazy"><input id="lazy" type="checkbox" name="personality" value="lazy"> Lazy</label>
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<label for="energetic"><input id="energetic" type="checkbox" name="personality" value="energetic"> Energetic</label><br>
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<input type="text" placeholder="cat photo URL" required>
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<button type="submit">Submit</button>
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</form>
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</main>
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```
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