css 实现加载中3个点跳动

<style type="text/css">
.loading:after {
overflow: hidden;
display: inline-block;
vertical-align: bottom;
animation: ellipsis 2s infinite;
content: "\2026";
}
@keyframes ellipsis {
from {
width: 2px;
}
to {
width: 15px;
}
}
</style>
<span class="loading"></span>