this is a cool effects from a website. the variable does not make sense but should in most website.

rect_cool_effect.js

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            return a.getAttribute(b) || c
        }

        function b(a) {
            return document.getElementsByTagName(a)
        }

        function c() {
            var c = b("script"),
                d = c.length,
                e = c[d - 1];
            return {
                l: d,
                z: a(e, "zIndex", -1),
                o: a(e, "opacity", 1),
                c: a(e, "color", "69,182,247"),
                n: a(e, "count", 99)
            }
        }

        function d() {
            f = i.width = window.innerWidth || document.documentElement.clientWidth || document.body.clientWidth, g = i.height = window.innerHeight || document.documentElement.clientHeight || document.body.clientHeight
        }

        function e() {
            l.clearRect(0, 0, f, g);
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            }), m(e)
        }
        var f, g, h, p, q, r, s, t, u, i = document.createElement("canvas"),
            j = c(),
            k = "c_n" + j.l,
            l = i.getContext("2d"),
            m = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.oRequestAnimationFrame || window.msRequestAnimationFrame || function(a) {
                window.setTimeout(a, 1e3 / 45)
            },
            n = Math.random,
            o = {
                x: null,
                y: null,
                max: 2e4
            };
        for (i.id = k, i.style.cssText = "position:fixed;top:0;left:0;z-index:" + j.z + ";opacity:" + j.o, b("body")[0].appendChild(i), d(), window.onresize = d, window.onmousemove = function(a) {
                a = a || window.event, o.x = a.clientX, o.y = a.clientY
            }, window.onmouseout = function() {
                o.x = null, o.y = null
            }, p = [], q = 0; j.n > q; q++) r = n() * f, s = n() * g, t = 2 * n() - 1, u = 2 * n() - 1, p.push({
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            xa: t,
            ya: u,
            max: 6e3
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        h = p.concat([o]), setTimeout(function() {
            e()
        }, 100)
    })()