animation-timing-function概述:获取或设置对象动画的过渡类型
animation-timing-function指定动画如何完成循环。
速度曲线定义动画从一组CSS样式更改为另一组所需的时间。
速度曲线用于平滑变化。
animation-timing-function: value;

animation-timing-function:linear;
-webkit-animation-timing-function:linear; /* Safari and Chrome */
/* Chrome, Safari 和 Opera */
#div1 {-webkit-animation-timing-function: linear;}
#div2 {-webkit-animation-timing-function: ease;}
#div3 {-webkit-animation-timing-function: ease-in;}
#div4 {-webkit-animation-timing-function: ease-out;}
#div5 {-webkit-animation-timing-function: ease-in-out;}
/* 标准语法 */
#div1 {animation-timing-function: linear;}
#div2 {animation-timing-function: ease;}
#div3 {animation-timing-function: ease-in;}
#div4 {animation-timing-function: ease-out;}
#div5 {animation-timing-function: ease-in-out;}
#div1 {animation-timing-function:cubic-bezier(0,0,0.25,1);}
#div2 {animation-timing-function:cubic-bezier(0.25,0.1,0.25,1);}
#div3 {animation-timing-function:cubic-bezier(0.42,0,1,1);}
#div4 {animation-timing-function:cubic-bezier(0,0,0.58,1);}
#div5 {animation-timing-function:cubic-bezier(0.42,0,0.58,1);}
/* Safari and Chrome: */
#div1 {-webkit-animation-timing-function:cubic-bezier(0,0,0.25,1);}
#div2 {-webkit-animation-timing-function:cubic-bezier(0.25,0.1,0.25,1);}
#div3 {-webkit-animation-timing-function:cubic-bezier(0.42,0,1,1);}
#div4 {-webkit-animation-timing-function:cubic-bezier(0,0,0.58,1);}
#div5 {-webkit-animation-timing-function:cubic-bezier(0.42,0,0.58,1);}