演示

<small id="colortap1"></small>
<script>
var colortap = function (r) {
    function t() {return b[Math.floor(Math.random() * b.length)]}
    function e() {return String.fromCharCode(94 * Math.random() + 33)}
    function n(r) {
        for(var n=document.createDocumentFragment(),i=0;r>i;i++){
            var l=document.createElement("span");
            l.textContent=e(),l.style.color=t(),n.appendChild(l)
        }
        return n;
    }
    function i() {
        var t = o[c.skillI];
        c.step ? c.step-- : (c.step = g, c.prefixP < l.length ? (c.prefixP >= 0 && (c.text += l[c.prefixP]), c.prefixP++) : "forward" === c.direction ? c.skillP < t.length ? (c.text += t[c.skillP], c.skillP++) : c.delay ? c.delay-- : (c.direction = "backward", c.delay = a) : c.skillP > 0 ? (c.text = c.text.slice(0, -1), c.skillP--) : (c.skillI = (c.skillI + 1) % o.length, c.direction = "forward")),
        r.textContent = c.text,
        r.appendChild(n(c.prefixP < l.length ? Math.min(s, s + c.prefixP) : Math.min(s, t.length - c.skillP))),
        setTimeout(i, d)
    }
    var l = "",
    o = ["资源-干货-技能-学习","公众号:SAS文库网","喜欢就点个关注吧！"].map(function (r) {return r + ""}),
    a = 2,g = 1,s = 5,d = 75,
    b = ["rgb(110,64,170)", "rgb(150,61,179)", "rgb(191,60,175)", "rgb(228,65,157)", "rgb(254,75,131)", "rgb(255,94,99)", "rgb(255,120,71)", "rgb(251,150,51)", "rgb(226,183,47)", "rgb(198,214,60)", "rgb(175,240,91)", "rgb(127,246,88)", "rgb(82,246,103)", "rgb(48,239,130)", "rgb(29,223,163)", "rgb(26,199,194)", "rgb(35,171,216)", "rgb(54,140,225)", "rgb(76,110,219)", "rgb(96,84,200)"],
    c = {text: "",prefixP: -s,skillI: 0,skillP: 0,direction: "forward",delay: a,step: g};i()
};
colortap(document.getElementById('colortap1'));
</script>