animation-fill-mode

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2015.

CSS 属性 animation-fill-mode 设置 CSS 动画在执行之前和之后如何将样式应用于其目标。

尝试一下

使用简写属性 animation 一次性设置所有动画属性通常很方便。

语法

css
/* Single animation */
animation-fill-mode: none;
animation-fill-mode: forwards;
animation-fill-mode: backwards;
animation-fill-mode: both;

/* Multiple animations */
animation-fill-mode: none, backwards;
animation-fill-mode: both, forwards, none;

值

none

当动画未执行时，动画将不会将任何样式应用于目标，而是已经赋予给该元素的 CSS 规则来显示该元素。这是默认值。

forwards

目标将保留由执行期间遇到的最后一个关键帧计算值。最后一个关键帧取决于animation-direction和animation-iteration-count的值：

animation-direction animation-iteration-count last keyframe encountered
normal even or odd 100% or to
reverse even or odd 0% or from
alternate even 0% or from
alternate odd 100% or to
alternate-reverse even 100% or to
alternate-reverse odd 0% or from
backwards

动画将在应用于目标时立即应用第一个关键帧中定义的值，并在animation-delay期间保留此值。第一个关键帧取决于animation-direction的值：

animation-direction first relevant keyframe
normal or alternate 0% or from
reverse or alternate-reverse 100% or to
both

动画将遵循forwards和backwards的规则，从而在两个方向上扩展动画属性。

备注： 当你在animation-*属性上指定多个以逗号分隔的值时，它们将根据值的数量以不同的方式分配给 animation-name 属性中指定的动画。有关更多信息，请参阅设置多个动画属性值。

正式语法

animation-fill-mode = 
  <single-animation-fill-mode>#  

<single-animation-fill-mode> = 
  none       |
  forwards   |
  backwards  |
  both

示例

你可以在以下示例中看到 animation-fill-mode 的效果。它演示了如何对于运行无限时间的动画，可以使其保持最终状态而不是恢复到原始状态（这是默认状态）。

HTML

html
<p>Move your mouse over the gray box!</p>
<div class="demo">
  <div class="growsandstays">This grows and stays big.</div>
  <div class="grows">This just grows.</div>
</div>

CSS

css
.demo {
  border-top: 100px solid #ccc;
  height: 300px;
}

@keyframes grow {
  0% {
    font-size: 0;
  }
  100% {
    font-size: 40px;
  }
}

.demo:hover .grows {
  animation-name: grow;
  animation-duration: 3s;
}

.demo:hover .growsandstays {
  animation-name: grow;
  animation-duration: 3s;
  animation-fill-mode: forwards;
}

更多示例请查看 CSS 动画 。

规范

Specification
CSS Animations Level 1
# animation-fill-mode
初始值none
适用元素all elements, ::before and ::after pseudo-elements
是否是继承属性否
计算值as specified
动画类型Not animatable

浏览器兼容性

BCD tables only load in the browser

参见