css - 动画 :after in css

Question

我想弄清楚为什么这个简单的代码不起作用。

http://jsfiddle.net/yq1ro6n5/

@keyframes testing {
    from: {font-size: 42px;}
    to: {font-size: 64px;}
}
a:after {
    content: "Hello!";
    animation: testing 1s infinite;
}

-

<a></a>

谁能解释一下？

Answer 1

像这样从关键帧中移除:

@keyframes testing {
from {
    font-size: 42px;
}
to {
    font-size: 64px;
}
}

a {
}
@keyframes testing {
    from {
        font-size: 42px;
    }
    to {
        font-size: 64px;
    }
}
a:after {
    content:"Hello!";
    animation: testing 3s infinite;
}

<a></a>