2018-10-10 22:03:03 +00:00
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---
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id: bad87fee1348bd9aedf04756
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2020-12-16 07:37:30 +00:00
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title: Class 选择器的优先级高于继承样式
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2018-10-10 22:03:03 +00:00
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challengeType: 0
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2019-12-13 05:47:57 +00:00
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videoUrl: 'https://scrimba.com/c/cGJDQug'
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forumTopicId: 18253
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2021-01-13 02:31:00 +00:00
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dashedName: override-styles-in-subsequent-css
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2018-10-10 22:03:03 +00:00
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2021-02-06 04:42:36 +00:00
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我们的 `pink-text` class 覆盖了 `body` 元素的 CSS 样式!
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2020-12-16 07:37:30 +00:00
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2021-02-06 04:42:36 +00:00
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我们刚刚证明了 class 会覆盖 `body` 的 CSS 样式。 那么下一个问题是,要怎么样才能覆盖 `pink-text` class 中所定义的样式?
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2020-12-16 07:37:30 +00:00
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# --instructions--
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2021-02-06 04:42:36 +00:00
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创建一个 `blue-text` class,将元素的颜色设置为蓝色。 将它放在 `pink-text` class 下面。
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2020-12-16 07:37:30 +00:00
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2021-08-02 14:05:44 +00:00
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将 `blue-text` class 应用于 `h1` 元素,看看它和该元素上的 `pink-text` class 哪一个会优先显示。
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2018-10-10 22:03:03 +00:00
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2021-08-02 14:05:44 +00:00
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将多个 class 属性应用于一个 HTML 元素,需以空格来间隔这些属性,例如:
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2018-10-10 22:03:03 +00:00
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2021-03-21 16:58:20 +00:00
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```html
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class="class1 class2"
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```
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2018-10-10 22:03:03 +00:00
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2021-08-02 14:05:44 +00:00
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**注意:** HTML 元素里应用的 class 的先后顺序无关紧要。
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2020-12-16 07:37:30 +00:00
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2021-02-06 04:42:36 +00:00
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但是,在 `<style>` 标签里面声明的 `class` 顺序十分重要,之后的声明会覆盖之前的声明。 第二个声明的优先级始终高于第一个声明。 由于 `.blue-text` 是在后面声明的,所以它的样式会覆盖 `.pink-text` 里的样式。
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2020-12-16 07:37:30 +00:00
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# --hints--
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2021-01-08 19:20:48 +00:00
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`h1` 元素应包含 `pink-text` class。
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2020-12-16 07:37:30 +00:00
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```js
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assert($('h1').hasClass('pink-text'));
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2018-10-10 22:03:03 +00:00
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```
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2021-01-08 19:20:48 +00:00
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`h1` 元素应包含 `blue-text` class。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert($('h1').hasClass('blue-text'));
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```
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2018-10-10 22:03:03 +00:00
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2021-01-08 19:20:48 +00:00
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`blue-text` 和 `pink-text` 需同时应用于 `h1` 元素上。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert($('.pink-text').hasClass('blue-text'));
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```
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2018-10-10 22:03:03 +00:00
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2021-01-08 19:20:48 +00:00
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`h1` 元素的颜色应为蓝色。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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```js
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assert($('h1').css('color') === 'rgb(0, 0, 255)');
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2018-10-10 22:03:03 +00:00
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```
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2019-12-13 05:47:57 +00:00
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2021-01-13 02:31:00 +00:00
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# --seed--
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## --seed-contents--
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```html
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<style>
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body {
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background-color: black;
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font-family: monospace;
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color: green;
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}
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.pink-text {
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color: pink;
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}
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</style>
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<h1 class="pink-text">Hello World!</h1>
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```
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2020-12-16 07:37:30 +00:00
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# --solutions--
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2021-01-13 02:31:00 +00:00
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```html
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<style>
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body {
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background-color: black;
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font-family: monospace;
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color: green;
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}
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.pink-text {
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color: pink;
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}
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.blue-text {
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color: blue;
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}
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</style>
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<h1 class="pink-text blue-text">Hello World!</h1>
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```
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