How to Get Started with CSS Animation

CSS animation: Dynamic effects beyond CSS transition

CSS animation is an advanced version of CSS transition. It supports infinite loops, uses keyframes to create complex effects, and can be paused during animation playback. This article will explore all aspects of CSS animation to help you easily master this powerful web design technology.

Create CSS animation: Keyframes and animation properties

To create a CSS animation, you first need to define a @keyframes rule that specifies the animation name and groups the keyframe rules. Then, apply the animation to the target element.

CSS animation can be controlled through a variety of attributes, including: animation-delay (animation delay), animation-duration (animation duration), animation-name (animation name), animation-timing-function (animation timing function), 🎜> (number of animation iterations), animation-iteration-count (animation direction), animation-direction (animation playback status), and animation-play-state (animation fill mode). animation-fill-mode

Animation control: Pause and loop

Use the

attribute to pause animation. Setting the animation-play-state property to animation-iteration-count can achieve infinite loops. infinite

Performance and accessibility: Use animation with caution

While CSS animation can enhance the user experience, it should be used with caution because it may pose a risk of accessibility, for example: patients with certain diseases may experience dizziness or nausea from the animation, while those with photosensitive epilepsy may have the potential to be used in people with photosensitive epilepsy. Epilepsy seizures caused by animation. In addition, the performance of animations is also affected by animation properties, and some properties may trigger reflow or redraw, resulting in performance degradation on low-performance devices.

Difference between animation and transition: Key differences

There are some key differences between CSS animations and their sister technology CSS transition:

• Elegant downgrade: Animation lacks an elegant downgrade mechanism. When the browser does not support it, the animation will be invalid and JavaScript is required as an alternative.
• Loop: Animation can be repeated, even repetitive indefinitely; while transitions are always limited.
• Keyframes: Animation uses keyframes to create more complex and detailed effects.
• Pause: Animation can be paused during playback cycle.

Browser compatibility: Mainstream browser support

The latest versions of all mainstream browsers support CSS animation. Firefox 15 and earlier require the

prefix; later does not. Internet Explorer 10 and 11, as well as all versions of Microsoft Edge, also supports prefixed animations. -moz-

Detection animation support: JavaScript method

CSS animation support can be detected in various ways. The first method is to test whether the window method of the CSSKeyframeRule object exists:

const hasAnimations = 'CSSKeyframeRule' in window;

If the browser supports @supports rules and CSS.supports() API, you can use the following methods:

const hasAnimations = CSS.supports('animation-duration: 2s');

Create the first animation: Keyframe rules and animation applications

First, define the animation using the @keyframes rule. @keyframesRules have two functions:

• Set the animation name
• Group keyframe rules

For example, create an animation called pulse:

@keyframes pulse {
    from {
        transform: scale(0.5);
        opacity: .8;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

Then, apply the animation to the element:

.pulse {
    animation: pulse 500ms;
}

Detailed explanation of animation attributes: carefully control animation effects

Although using animation shorthand attributes is simpler, sometimes using long format attributes is clearer. The following are the long format animation properties:

Properties

Description

Initial Value

animation-delay

Waiting time before animation execution

0s (Execute now)

animation-duration

Animation cycle duration

0s (no animation)

animation-name

属性	描述	初始值
animation-delay	动画执行前的等待时间	0s (立即执行)
animation-duration	动画周期持续时间	0s (无动画)
animation-name	@keyframes规则的名称	none
animation-timing-function	计算起始状态和结束状态之间值的计算方式	ease
animation-iteration-count	动画重复次数	1
animation-direction	动画是否反向播放	normal (不反向)
animation-play-state	动画是运行还是暂停	running
animation-fill-mode	指定动画未运行时应用的属性值	none

The name of the rule

none

animation-timing-function

How to calculate the value between the start and end states

ease

animation-iteration-count

Number of animation repetitions

1

animation-direction

Is the animation played backward?

normal (not reverse)

animation-play-state

Is the animation running or pausing

running

animation-fill-mode

Specify the attribute value applied when the animation is not running

none

Loop animation: animation-iteration-count attribute

Setting the animation-iteration-count property to infinite can make the animation loop infinitely.

Animation direction: animation-direction attribute

The

animation-direction attribute accepts four values: normal, reverse, alternate, and alternate-reverse, which are used to control the playback direction of the animation.

Percent Keyframes: Create more complex animation sequences

More complex animation sequences can be created using percentage keyframes.

Animation fill mode: animation-fill-mode attribute

animation-fill-mode Attributes control the element style before and after the animation begins.

Pause animation: animation-play-state attribute

Use the animation-play-state attribute to pause and restore animations.

Detection of animation events: animationstart, animationend and animationitation events

You can use JavaScript to listen for animationstart, animationend and animationiteration events.

Performance optimization: Select the appropriate animation attributes

Some properties perform better than other properties. Avoid animations of properties that trigger reflow or redraw.

FAQ

The article also includes frequently asked questions about CSS animation, covering the differences between CSS animation and CSS transition, animation speed control, the role of @keyframes rules, layout animation, reverse playback animation, animation-fill-mode attributes, Pause animation, infinite loop animation, SVG element animation, and the differences between animation-delay and animation-end-delay.

By studying this article, you will be able to create more refined and complex CSS animation effects to improve the interactivity and user experience of the web page. Remember that when using animations, you always prioritize performance and accessibility.

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