Bem, na verdade existe uma maneira pura de CSS de fazer isso.
Peguei o exemplo do CSS Tricks, mas fiz também para ser compatível com o Internet Explorer (testei no 10+).
Verifique a demonstração: http://jsfiddle.net/Roobyx/AT6v6/2/
HTML:
<h4 id="searching-ellipsis"> Searching
<span>.</span>
<span>.</span>
<span>.</span>
</h4>
CSS:
@-webkit-keyframes opacity {
0% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=100);
opacity: 1;
}
100% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=0);
opacity: 0;
}
}
@-moz-keyframes opacity {
0% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=100);
opacity: 1;
}
100% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=0);
opacity: 0;
}
}
@-webkit-keyframes opacity {
0% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=100);
opacity: 1;
}
100% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=0);
opacity: 0;
}
}
@-moz-keyframes opacity {
0% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=100);
opacity: 1;
}
100% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=0);
opacity: 0;
}
}
@-o-keyframes opacity {
0% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=100);
opacity: 1;
}
100% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=0);
opacity: 0;
}
}
@keyframes opacity {
0% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=100);
opacity: 1;
}
100% {
filter: progid:DXImageTransform.Microsoft.Alpha(Opacity=0);
opacity: 0;
}
}
#searching-ellipsis span {
-webkit-animation-name: opacity;
-webkit-animation-duration: 1s;
-webkit-animation-iteration-count: infinite;
-moz-animation-name: opacity;
-moz-animation-duration: 1s;
-moz-animation-iteration-count: infinite;
-ms-animation-name: opacity;
-ms-animation-duration: 1s;
-ms-animation-iteration-count: infinite;
}
#searching-ellipsis span:nth-child(2) {
-webkit-animation-delay: 100ms;
-moz-animation-delay: 100ms;
-ms-animation-delay: 100ms;
-o-animation-delay: 100ms;
animation-delay: 100ms;
}
#searching-ellipsis span:nth-child(3) {
-webkit-animation-delay: 300ms;
-moz-animation-delay: 300ms;
-ms-animation-delay: 300ms;
-o-animation-delay: 300ms;
animation-delay: 300ms;
}