137 lines
4.5 KiB
Markdown
137 lines
4.5 KiB
Markdown
---
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id: bad87fee1348bd9aed108826
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title: Target a Specific Child of an Element Using jQuery
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required:
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- link: 'https://cdnjs.cloudflare.com/ajax/libs/animate.css/3.2.0/animate.css'
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challengeType: 6
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forumTopicId: 18315
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localeTitle: 使用 jQuery 选择元素的特定子元素
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---
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## Description
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<section id='description'>
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你已经看到了为什么 id 属性对于 jQuery 选择器选取标签非常方便，但这并不适用于所有情景。
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幸运的是，jQuery 有一些其他的方法可以选取正确的标签。
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jQuery 可以用<code>CSS 选择器（CSS Selectors）</code>选取标签。<code>target:nth-child(n)</code>CSS 选择器可以选取所有的第 n 个标签并设置目标属性和目标样式。
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下面的代码展示了给每个区域（well）的第 3 个标签设置<code>bounce</code>类：
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<code>$(".target:nth-child(3)").addClass("animated bounce");</code>
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请给每个区域（well）的第 2 个标签设置<code>bounce</code>类，必须用<code>target</code>类选取标签。
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</section>
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## Instructions
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<section id='instructions'>
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</section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: <code>target</code>标签中的第二个标签应该有弹性的动画效果。
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testString: assert($(".target:nth-child(2)").hasClass("animated") && $(".target:nth-child(2)").hasClass("bounce"));
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- text: 应该仅两个标签有弹性的动画效果。
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testString: assert($(".animated.bounce").length === 2);
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- text: 应该用<code>:nth-child()</code>选择器修改这些标签。
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testString: assert(code.match(/\:nth-child\(/g));
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- text: 仅用 jQuery 给标签添加类。
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testString: assert(code.match(/\$\(".target:nth-child\(2\)"\)/g) || code.match(/\$\('.target:nth-child\(2\)'\)/g) || code.match(/\$\(".target"\).filter\(":nth-child\(2\)"\)/g) || code.match(/\$\('.target'\).filter\(':nth-child\(2\)'\)/g));
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='html-seed'>
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```html
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<script>
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$(document).ready(function() {
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$("#target1").css("color", "red");
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$("#target1").prop("disabled", true);
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$("#target4").remove();
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$("#target2").appendTo("#right-well");
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$("#target5").clone().appendTo("#left-well");
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$("#target1").parent().css("background-color", "red");
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$("#right-well").children().css("color", "orange");
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});
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</script>
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<!-- 请修改本行以上的代码 -->
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<div class="container-fluid">
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<h3 class="text-primary text-center">jQuery Playground</h3>
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<div class="row">
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<div class="col-xs-6">
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<h4>#left-well</h4>
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<div class="well" id="left-well">
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<button class="btn btn-default target" id="target1">#target1</button>
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<button class="btn btn-default target" id="target2">#target2</button>
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<button class="btn btn-default target" id="target3">#target3</button>
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</div>
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</div>
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<div class="col-xs-6">
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<h4>#right-well</h4>
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<div class="well" id="right-well">
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<button class="btn btn-default target" id="target4">#target4</button>
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<button class="btn btn-default target" id="target5">#target5</button>
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<button class="btn btn-default target" id="target6">#target6</button>
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</div>
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</div>
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</div>
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</div>
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```html
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<script>
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$(document).ready(function() {
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$("#target1").css("color", "red");
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$("#target1").prop("disabled", true);
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$("#target4").remove();
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$("#target2").appendTo("#right-well");
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$("#target5").clone().appendTo("#left-well");
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$("#target1").parent().css("background-color", "red");
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$("#right-well").children().css("color", "orange");
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$(".target:nth-child(2)").addClass("animated bounce");
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});
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</script>
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<!-- Only change code above this line. -->
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<div class="container-fluid">
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<h3 class="text-primary text-center">jQuery Playground</h3>
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<div class="row">
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<div class="col-xs-6">
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<h4>#left-well</h4>
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<div class="well" id="left-well">
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<button class="btn btn-default target" id="target1">#target1</button>
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<button class="btn btn-default target" id="target2">#target2</button>
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<button class="btn btn-default target" id="target3">#target3</button>
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</div>
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</div>
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<div class="col-xs-6">
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<h4>#right-well</h4>
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<div class="well" id="right-well">
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<button class="btn btn-default target" id="target4">#target4</button>
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<button class="btn btn-default target" id="target5">#target5</button>
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<button class="btn btn-default target" id="target6">#target6</button>
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</div>
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</div>
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</div>
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</div>
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```
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</section>
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