freeCodeCamp/curriculum/challenges/chinese-traditional/01-responsive-web-design/applied-visual-design/make-a-css-heartbeat-using-an-infinite-animation-count.md

---
id: 587d78a8367417b2b2512ae4
title: 使用無限的動畫計數製作 CSS 心跳
challengeType: 0
videoUrl: 'https://scrimba.com/c/cDZpDUr'
forumTopicId: 301062
dashedName: make-a-css-heartbeat-using-an-infinite-animation-count
---

# --description--

這也是一個用 `animation-iteration-count` 屬性創造持續動畫的例子，它基於我們在前面挑戰中創建的心形。

心跳動畫的每一秒包含兩個部分。 `heart` 元素（包括 `:before` 和 `:after`）使用 `transform` 屬性改變其大小，背景 `div` 使用 `background` 屬性改變其顏色。

# --instructions--

給 `back` class 和 the `heart` class 添加 `animation-iteration-count` 屬性，將屬性值設置爲 `infinite`，使心保持跳動。 `heart:before` 和 `heart:after` 所選擇的元素則不需要添加動畫屬性。

# --hints--

`heart` class 的 `animation-iteration-count` 的屬性值應爲 `infinite`。

```js
assert($('.heart').css('animation-iteration-count') == 'infinite');
```

`back` class 的 `animation-iteration-count` 的屬性值應爲 `infinite`。

```js
assert($('.back').css('animation-iteration-count') == 'infinite');
```

# --seed--

## --seed-contents--

```html
<style>
  .back {
    position: fixed;
    padding: 0;
    margin: 0;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: white;
    animation-name: backdiv;
    animation-duration: 1s;

  }

  .heart {
    position: absolute;
    margin: auto;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background-color: pink;
    height: 50px;
    width: 50px;
    transform: rotate(-45deg);
    animation-name: beat;
    animation-duration: 1s;

  }
  .heart:after {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: 0px;
    left: 25px;
  }
  .heart:before {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: -25px;
    left: 0px;
  }

  @keyframes backdiv {
    50% {
      background: #ffe6f2;
    }
  }

  @keyframes beat {
    0% {
      transform: scale(1) rotate(-45deg);
    }
    50% {
      transform: scale(0.6) rotate(-45deg);
    }
  }

</style>
<div class="back"></div>
<div class="heart"></div>
```

# --solutions--

```html
<style>
  .back {
    position: fixed;
    padding: 0;
    margin: 0;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: white;
    animation-name: backdiv;
    animation-duration: 1s;
    animation-iteration-count: infinite;
  }

  .heart {
    position: absolute;
    margin: auto;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background-color: pink;
    height: 50px;
    width: 50px;
    transform: rotate(-45deg);
    animation-name: beat;
    animation-duration: 1s;
    animation-iteration-count: infinite;
  }
  .heart:after {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: 0px;
    left: 25px;
  }
  .heart:before {
    background-color: pink;
    content: "";
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: -25px;
    left: 0px;
  }

  @keyframes backdiv {
    50% {
      background: #ffe6f2;
    }
  }

  @keyframes beat {
    0% {
      transform: scale(1) rotate(-45deg);
    }
    50% {
      transform: scale(0.6) rotate(-45deg);
    }
  }
</style>
<div class="back"></div>
<div class="heart"></div>
```