代码简洁，性能恐怖，使用方式如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>测试效果</title>
<style media="screen">
.writer::after {
content: "|";
animation: flicker .8s ease infinite;
animation-direction: reverse;
}
@keyframes flicker {
from {
opacity: 1;
}
to {
opacity: 0;
}
}
</style>
</head>
<body>
<span class="writer" id="typing"></span>
<script src="../lib/index.js" charset="utf-8"></script>
<script type="text/javascript">
var writer = new TypeWriter({
container: document.querySelector('#typing'),
strs: ['hello', 'world', '23333333333'],
delay: 200
});
</script>
</body>
</html>
});