<a href="javascript:" class="login">登录中<span class="dotting"></span></a>

 .dotting { display: inline-block; width: 10px; min-height: 2px;padding-right: 2px;border-left: 2px solid currentColor; border-right: 2px solid currentColor;background-color: currentColor; background-clip: content-box;box-sizing: border-box;-webkit-animation: dot 1.5s infinite step-start both;animation: dot 1.5s infinite step-start both;*zoom: expression(this.innerHTML = '...');  /*IE7 */}.dotting:before { content: '...'; } /* IE8 */.dotting::before { content: ''; }:root .dotting { margin-left: 2px; padding-left: 2px; } /* IE9+ */@-o-keyframes dot {25% { border-color: transparent; background-color: transparent; }50% { border-right-color: transparent; background-color: transparent; }75% { border-right-color: transparent; }}@-ms-keyframes dot {25% { border-color: transparent; background-color: transparent; }50% { border-right-color: transparent; background-color: transparent; }75% { border-right-color: transparent; }}@-moz-keyframes dot {25% { border-color: transparent; background-color: transparent; }50% { border-right-color: transparent; background-color: transparent; }75% { border-right-color: transparent; }}@-webkit-keyframes dot {25% { border-color: transparent; background-color: transparent; }50% { border-right-color: transparent; background-color: transparent; }75% { border-right-color: transparent; }}@keyframes dot {25% { border-color: transparent; background-color: transparent; }50% { border-right-color: transparent; background-color: transparent; }75% { border-right-color: transparent; }}