div{ background: pink; height: 2px; width: 1000px; animation-name: shake ; animation-iteration-count: infinite; animation-duration: 6s; /* animation: name duration timing-function delay iteration-count direction fill-mode; */ /* animation: name duration timing-function 等待时间 iteration-count direction fill-mode; */ } @keyframes shake{ 0%{ width:15%; background: pink; } 100%{ width: 100%; background:red; } }