css

.print{
    width:250px;
    white-space:nowrap;
    overflow:hidden;
    -webkit-animation: dy 3s steps(60, end) infinite;
    animation: dy 3s steps(50, end) infinite;
}
@-webkit-keyframes dy{
    from { width: 0;}
}
@keyframes dy{
    from { width: 0;}
}

html:

<p class="print">Rookie-Front end learning</p>

效果：

Rookie-Front end learning