uniapp里：
CSS 动画播放时，会发生以下三个事件：
animationstart -CSS 动画开始后触发
animationiteration - CSS 动画重复播放时触发
animationend - CSS 动画完成后触发

 @animationstart='animationstart'
 @animationiteration='animationiteration'
 @animationend ='animationend'

 

其他方式：
 

var css3Am = document.querySelector("#css3Am");


css3Am.addEventListener("animationstart",function(e){
    console.log("animationstart");
},false);


css3Am.addEventListener("animationiteration",function(e){
    console.log("animationiteration");
},false);


css3Am.addEventListener("animationend",function(e){
    console.log("animationend");
},false);

不同的浏览器要求使用不同的前缀：

No prefix: animationstart, animationiteration, animationend
Webkit: webkitAnimationStart, webkitAnimationIteration, webkitAnimationEnd
Mozilla: mozAnimationStart, mozAnimationIteration, mozAnimationEnd
MS:MSAnimationStart, MSAnimationIteration, MSAnimationEnd
O : oAnimationStart, oAnimationIteration, oAnimationEnd