请问为什么动画效果在首次运行完ball1,ball2,ball3后再继续运行就没反应了~我明明加上了二次运行ball1,ball2,ball3啊！
<!doctype>
<!DOCTYPE html>
<html>
<head>
<title>promise animation</title>
<style type="text/css">
.ball{
width: 40px;
height: 40px;
border-radius: 20px;
}
.ball1{
background-color: red;
}
.ball2{
background-color: yellow;
}
.ball3{
background-color: green;
}
</style>
<script type="text/javascript" src="./node_modules/bluebird/js/browser/bluebird.js"></script>
</head>
<body>
<div class="ball ball1" style="margin-left: 0px;"></div>
<div class="ball ball2" style="margin-left: 0px;"></div>
<div class="ball ball3" style="margin-left: 0px;"></div>
<script type="text/javascript">
var ball1=document.querySelector('.ball1')
var ball2=document.querySelector('.ball2')
var ball3=document.querySelector('.ball3')
// function animate(ball,distance,cb){
// setTimeout(function(){
// var marginLeft=parseInt(ball.style.marginLeft,10)
// if(marginLeft === distance){
// cb && cb()
// }else if (marginLeft<distance) {
// marginLeft++
// }else{
// marginLeft--
// }
// ball.style.marginLeft=marginLeft + 'px'
// animate(ball,distance,cb)
// },13)
// }
// animate(ball1,100,function(){
// animate(ball2,200,function(){
// animate(ball3,300,function(){
// animate(ball3,150,function(){
// animate(ball2,150,function(){
// animate(ball1,150,function(){
// })
// })
// })
// })
// })
// })
var Promise = window.Promise
function promiseAnimate(ball,distance){
return new Promise(function(resolve,reject){
function _animate(){
setTimeout(function(){
var marginLeft=parseInt(ball.style.marginLeft,10)
if(marginLeft === distance){
resolve()
}else if (marginLeft<distance) {
marginLeft++
}else{
marginLeft--
}
ball.style.marginLeft=marginLeft + 'px'
_animate()
},13)
}
_animate()
})
}
promiseAnimate(ball1,100)
.then(function(){
return promiseAnimate(ball2,200)
})
.then(function(){
return promiseAnimate(ball3,300)
})
.then(function(){
return promiseAnimate(ball3,150)
})
.then(function(){
return promiseAnimate(ball2,150)
})
.then(function(){
return promiseAnimate(ball1,150)
})
</script>
</body>
</html>
