cursor animation

!(function (e, t, a) {
    function n() {
        c(".circle{width: 10px;height: 10px;position: fixed;background: #f00;border-radius:50%}"), o(), r();
    }
    function r() {
        for (var e = 0; e < d.length; e++)
            d[e].alpha <= 0
                ? (t.body.removeChild(d[e].el), d.splice(e, 1))
                : (d[e].y--,
                  (d[e].scale += 0.004),
                  (d[e].alpha -= 0.013),
                  (d[e].el.style.cssText = "left:" + d[e].x + "px;top:" + d[e].y + "px;opacity:" + d[e].alpha + ";transform:scale(" + d[e].scale + "," + d[e].scale + ") rotate(45deg);background:" + d[e].color + ";z-index:99999"));
        requestAnimationFrame(r);
    }
    function o() {
        var t = "function" == typeof e.onclick && e.onclick;
        e.onclick = function (e) {
            t && t(), i(e);
        };
    }
    function i(e) {
        var a = t.createElement("div");
        (a.className = "circle"), d.push({ el: a, x: e.clientX - 5, y: e.clientY - 5, scale: 1, alpha: 1, color: s() }), t.body.appendChild(a);
    }
    function c(e) {
        var a = t.createElement("style");
        a.type = "text/css";
        try {
            a.appendChild(t.createTextNode(e));
        } catch (t) {
            a.styleSheet.cssText = e;
        }
        t.getElementsByTagName("head")[0].appendChild(a);
    }
    function s() {
        return "rgb(154 117 36)";
    }
    var d = [];
    (e.requestAnimationFrame = (function () {
        return (
            e.requestAnimationFrame ||
            e.webkitRequestAnimationFrame ||
            e.mozRequestAnimationFrame ||
            e.oRequestAnimationFrame ||
            e.msRequestAnimationFrame ||
            function (e) {
                setTimeout(e, 1e3 / 60);
            }
        );
    })()),
        n();
})(window, document);