元素:animationiteration 事件
animationiteration
事件在 CSS 动画 的一次迭代结束,而另一次迭代开始时触发。此事件不会与 animationend
事件同时发生,因此对于 animation-iteration-count
为 1 的动画不会发生。
语法
在 addEventListener()
等方法中使用事件名称,或设置事件处理程序属性。
js
addEventListener("animationiteration", (event) => {});
onanimationiteration = (event) => {};
事件类型
一个 AnimationEvent
。继承自 Event
。
事件属性
还继承了其父类 Event
的属性.
AnimationEvent.animationName
只读-
包含生成动画的
animation-name
值的字符串。 AnimationEvent.elapsedTime
只读-
一个
float
,表示此事件触发时动画已运行的时间量(以秒为单位),不包括动画暂停的任何时间。对于animationstart
事件,elapsedTime
为0.0
,除非animation-delay
的值为负数,在这种情况下,事件将以包含(-1 * delay)
的elapsedTime
触发。 AnimationEvent.pseudoElement
只读-
一个以
'::'
开头的字符串,包含动画运行的 伪元素 的名称。如果动画不在伪元素上运行,而是在元素上运行,则为空字符串:''
。
示例
此代码使用 animationiteration
来跟踪动画完成的迭代次数
js
const animated = document.querySelector(".animated");
let iterationCount = 0;
animated.addEventListener("animationiteration", () => {
iterationCount++;
console.log(`Animation iteration count: ${iterationCount}`);
});
相同,但使用 onanimationiteration
事件处理程序属性
js
const animated = document.querySelector(".animated");
let iterationCount = 0;
animated.onanimationiteration = () => {
iterationCount++;
console.log(`Animation iteration count: ${iterationCount}`);
};
实时示例
HTML
html
<div class="animation-example">
<div class="container">
<p class="animation">You chose a cold night to visit our planet.</p>
</div>
<button class="activate" type="button">Activate animation</button>
<div class="event-log"></div>
</div>
CSS
css
.container {
height: 3rem;
}
.event-log {
width: 25rem;
height: 2rem;
border: 1px solid black;
margin: 0.2rem;
padding: 0.2rem;
}
.animation.active {
animation-duration: 2s;
animation-name: slidein;
animation-iteration-count: 2;
}
@keyframes slidein {
from {
transform: translateX(100%) scaleX(3);
}
to {
transform: translateX(0) scaleX(1);
}
}
JavaScript
js
const animation = document.querySelector("p.animation");
const animationEventLog = document.querySelector(
".animation-example>.event-log",
);
const applyAnimation = document.querySelector(
".animation-example>button.activate",
);
let iterationCount = 0;
animation.addEventListener("animationstart", () => {
animationEventLog.textContent = `${animationEventLog.textContent}'animation started' `;
});
animation.addEventListener("animationiteration", () => {
iterationCount++;
animationEventLog.textContent = `${animationEventLog.textContent}'animation iterations: ${iterationCount}' `;
});
animation.addEventListener("animationend", () => {
animationEventLog.textContent = `${animationEventLog.textContent}'animation ended'`;
animation.classList.remove("active");
applyAnimation.textContent = "Activate animation";
});
animation.addEventListener("animationcancel", () => {
animationEventLog.textContent = `${animationEventLog.textContent}'animation canceled'`;
});
applyAnimation.addEventListener("click", () => {
animation.classList.toggle("active");
animationEventLog.textContent = "";
iterationCount = 0;
const active = animation.classList.contains("active");
applyAnimation.textContent = active
? "Cancel animation"
: "Activate animation";
});
结果
规范
规范 |
---|
CSS 动画级别 1 # eventdef-globaleventhandlers-animationiteration |
浏览器兼容性
BCD 表格仅在浏览器中加载