HTML代码
<html xmlns="http://www.w3.org/1999/xhtml"><head>
<title>用CSS3动画给一个小球创建跳跃的动画效果</title>
<link rel="stylesheet" type="text/css" href="index.css" />
</head>
<body>
<section class="main">
<div id="ballWrapper">
<div id="ball"></div>
<div id="ballShadow"></div>
</div>
</section>
</body>
</html>
CSS代码（创建一个与html同目录的index.css文件）
#ballWrapper{position:fixedtop:35%left:50%z-index:100margin-left:-70pxwidth:140pxheight:300pxcursor:pointer-webkit-transition:all 5s linear 0s-moz-transition:all 5s linear 0stransition:all 5s linear 0s-webkit-transform:scale(1)-moz-transform:scale(1)-o-transform:scale(1)transform:scale(1)-ms-transform:scale(1)}#ballWrapper:active{cursor:pointer-webkit-transform:scale(0)-moz-transform:scale(0)-o-transform:scale(0)transform:scale(0)-ms-transform:scale(0)}
#ball{position:absolutetop:0z-index:11width:140pxheight:140pxborder-radius:70pxbackground:#bbbbackground:url(data:image/svg+xml background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(187,187,187,1)), color-stop(99%,rgba(119,119,119,1))) background: -webkit-linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) background: -o-linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) background: -ms-linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) background: linear-gradient(top, rgba(187,187,187,1) 0%,rgba(119,119,119,1) 99%) box-shadow: inset 0 -5px 15px rgba(255,255,255,0.4), inset -2px -1px 40px rgba(0,0,0,0.4), 0 0 1px #000 cursor: pointer base64,PD94bWwgdmVyc2lvbj0iMS4wIiA/Pgo8c3ZnIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgd2lkdGg9IjEwMCUiIGhlaWdodD0iMTAwJSIgdmlld0JveD0iMCAwIDEgMSIgcHJlc2VydmVBc3BlY3RSYXRpbz0ibm9uZSI+CiAgPGxpbmVhckdyYWRpZW50IGlkPSJncmFkLXVjZ2ctZ2VuZXJhdGVkIiBncmFkaWVudFVuaXRzPSJ1c2VyU3BhY2VPblVzZSIgeDE9IjAlIiB5MT0iMCUiIHgyPSIwJSIgeTI9IjEwMCUiPgogICAgPHN0b3Agb2Zmc2V0PSIwJSIgc3RvcC1jb2xvcj0iI2JiYmJiYiIgc3RvcC1vcGFjaXR5PSIxIi8+CiAgICA8c3RvcCBvZmZzZXQ9Ijk5JSIgc3RvcC1jb2xvcj0iIzc3Nzc3NyIgc3RvcC1vcGFjaXR5PSIxIi8+CiAgPC9saW5lYXJHcmFkaWVudD4KICA8cmVjdCB4PSIwIiB5PSIwIiB3aWR0aD0iMSIgaGVpZ2h0PSIxIiBmaWxsPSJ1cmwoI2dyYWQtdWNnZy1nZW5lcmF0ZWQpIiAvPgo8L3N2Zz4=)background:-moz-linear-gradient(top,rgba(187,187,187,1) 0,rgba(119,119,119,1) 99%)filter:progid:DXImageTransform.Microsoft.gradient( startColorstr='#bbbbbb', endColorstr='#777777', GradientType=0 )-webkit-animation:jump 1s infinite-moz-animation:jump 1s infinite-o-animation:jump 1s infinite-ms-animation:jump 1s infiniteanimation:jump 1s infinite}
#ball::after{position:absolutetop:10pxleft:30pxz-index:10width:80pxheight:40pxborder-radius:40px/20pxbackground:url(data:image/svg+xml background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,rgba(232,232,232,1)), color-stop(1%,rgba(232,232,232,1)), color-stop(100%,rgba(255,255,255,0))) background: -webkit-linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) background: -o-linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) background: -ms-linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) background: linear-gradient(top, rgba(232,232,232,1) 0%,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%) content: "" base64,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)background:-moz-linear-gradient(top,rgba(232,232,232,1) 0,rgba(232,232,232,1) 1%,rgba(255,255,255,0) 100%)filter:progid:DXImageTransform.Microsoft.gradient( startColorstr='#e8e8e8', endColorstr='#00ffffff', GradientType=0 )}
#ballShadow{position:absolutebottom:0left:50%z-index:10margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-webkit-transform:scaleY(.3)-moz-transform:scaleY(.3)-o-transform:scaleY(.3)transform:scaleY(.3)-ms-transform:scaleY(.3)-webkit-animation:shrink 1s infinite-moz-animation:shrink 1s infinite-o-animation:shrink 1s infinite-ms-animation:shrink 1s infiniteanimation:shrink 1s infinite}
@-webkit-keyframes jump{0%{top:0-webkit-animation-timing-function:ease-in}
50%{top:140pxheight:140px-webkit-animation-timing-function:ease-out}
55%{top:160pxheight:120pxborder-radius:70px/60px-webkit-animation-timing-function:ease-in}
65%{top:120pxheight:140pxborder-radius:70px-webkit-animation-timing-function:ease-out}
95%{top:0-webkit-animation-timing-function:ease-in}
100%{top:0-webkit-animation-timing-function:ease-in}
}
@-moz-keyframes jump{0%{top:0-moz-animation-timing-function:ease-in}
50%{top:140pxheight:140px-moz-animation-timing-function:ease-out}
55%{top:160pxheight:120pxborder-radius:70px/60px-moz-animation-timing-function:ease-in}
65%{top:120pxheight:140pxborder-radius:70px-moz-animation-timing-function:ease-out}
95%{top:0-moz-animation-timing-function:ease-in}
100%{top:0-moz-animation-timing-function:ease-in}
}
@-o-keyframes jump{0%{top:0-o-animation-timing-function:ease-in}
50%{top:140pxheight:140px-o-animation-timing-function:ease-out}
55%{top:160pxheight:120pxborder-radius:70px/60px-o-animation-timing-function:ease-in}
65%{top:120pxheight:140pxborder-radius:70px-o-animation-timing-function:ease-out}
95%{top:0-o-animation-timing-function:ease-in}
100%{top:0-o-animation-timing-function:ease-in}
}
@-ms-keyframes jump{0%{top:0-ms-animation-timing-function:ease-in}
50%{top:140pxheight:140px-ms-animation-timing-function:ease-out}
55%{top:160pxheight:120pxborder-radius:70px/60px-ms-animation-timing-function:ease-in}
65%{top:120pxheight:140pxborder-radius:70px-ms-animation-timing-function:ease-out}
95%{top:0-ms-animation-timing-function:ease-in}
100%{top:0-ms-animation-timing-function:ease-in}
}
@keyframes jump{0%{top:0animation-timing-function:ease-in}
50%{top:140pxheight:140pxanimation-timing-function:ease-out}
55%{top:160pxheight:120pxborder-radius:70px/60pxanimation-timing-function:ease-in}
65%{top:120pxheight:140pxborder-radius:70pxanimation-timing-function:ease-out}
95%{top:0animation-timing-function:ease-in}
100%{top:0animation-timing-function:ease-in}
}
@-webkit-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-webkit-animation-timing-function:ease-in}
50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-webkit-animation-timing-function:ease-out}
100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-webkit-animation-timing-function:ease-in}
}
@-moz-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-moz-animation-timing-function:ease-in}
50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-moz-animation-timing-function:ease-out}
100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-moz-animation-timing-function:ease-in}
}
@-o-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-o-animation-timing-function:ease-in}
50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-o-animation-timing-function:ease-out}
100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-o-animation-timing-function:ease-in}
}
@-ms-keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-ms-animation-timing-function:ease-in}
50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)-ms-animation-timing-function:ease-out}
100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)-ms-animation-timing-function:ease-in}
}
@keyframes shrink{0%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)animation-timing-function:ease-in}
50%{bottom:30pxmargin-left:-10pxwidth:20pxheight:5pxborder-radius:20pxbackground:rgba(20,20,20,.3)box-shadow:0 0 20px 35px rgba(20,20,20,.3)animation-timing-function:ease-out}
100%{bottom:0margin-left:-30pxwidth:60pxheight:75pxborder-radius:30px/40pxbackground:rgba(20,20,20,.1)box-shadow:0 0 20px 35px rgba(20,20,20,.1)animation-timing-function:ease-in}
}
定义和用法通过 @keyframes 规则，您能够创建动画。
创建动画的原理是，将一套 CSS 样式逐渐变化为另一套样式。
在动画过程中，您能够多次改变这套 CSS 样式。
以百分比来规定改变发生的时间，或者通过关键词 "from" 和 "to"，等价于 0% 和 100%。
0% 是动画的开始时间，100% 动画的结束时间。
为了获得最佳的浏览器支持，您应该始终定义 0% 和 100% 选择器。
语法
@keyframes animationname {keyframes-selector {css-styles}}
值
animationname 必需。定义动画的名称。
keyframes-selector 必需。动画时长的百分比。
合法的值：
0-100%
from（与 0% 相同）
to（与 100% 相同）
css-styles 必需。一个或多个合法的 CSS 样式属性
以上是w3chool中的介绍。
已知的BUG
iOS 6.1及以下不支持伪元素动画。iOS 7和更高的版本的伪元素动画会些问题。
Firefox 不支持@keyframes 在内联元素的使用。
在Chorme中，如果使用了steps(x , start) ，animation-fill-mode backwards将会出错。
在IE10和IE11中，@keyframes不能在媒体查询@media内使用。
而且要注意几点:
1@keyframes 不能实现突变的状态变化
2@keyframes会改变对象的属性
看你截图显示，应该是你的编辑器太老了，它不能识别新增的@keyframes
如果在浏览器中不能实现，最好用chrome测试，如果还有问题，就排错。很大可能是上面两条。
