82 lines
1.6 KiB
Markdown
82 lines
1.6 KiB
Markdown
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---
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id: 587d78a3367417b2b2512acf
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title: 使用 z-index 屬性更改重疊元素的位置
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challengeType: 0
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videoUrl: 'https://scrimba.com/c/cM94aHk'
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forumTopicId: 301046
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dashedName: change-the-position-of-overlapping-elements-with-the-z-index-property
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---
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# --description--
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當一些元素在位置上重疊時（例如，使用 `position: absolute | relative | fixed | sticky` 時），在 HTML 裏後出現的元素會默認顯示在更早出現的元素的上面。 你可以使用 `z-index` 屬性指定元素的堆疊次序。 `z-index` 的取值是整數，數值大的元素會疊放到數值小的元素上面。
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# --instructions--
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給 class 爲 `first` 的元素（紅色的方塊）添加 `z-index` 屬性並將屬性值設置爲 2，使它顯示在藍色方塊的上方。
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# --hints--
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class 爲 `first` 的元素的 `z-index` 屬性值應爲 2。
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```js
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assert($('.first').css('z-index') == '2');
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```
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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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div {
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width: 60%;
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height: 200px;
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margin-top: 20px;
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}
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.first {
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background-color: red;
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position: absolute;
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}
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.second {
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background-color: blue;
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position: absolute;
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left: 40px;
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top: 50px;
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z-index: 1;
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}
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</style>
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<div class="first"></div>
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<div class="second"></div>
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```
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# --solutions--
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```html
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<style>
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div {
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width: 60%;
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height: 200px;
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margin-top: 20px;
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}
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.first {
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background-color: red;
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position: absolute;
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z-index: 2;
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}
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.second {
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background-color: blue;
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position: absolute;
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left: 40px;
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top: 50px;
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z-index: 1;
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}
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</style>
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<div class="first"></div>
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<div class="second"></div>
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```
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