208 lines
9.7 KiB
HTML
208 lines
9.7 KiB
HTML
<!DOCTYPE html>
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<html>
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<head>
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<meta charset="utf-8">
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<title>背景连线动画</title>
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<style>
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html,
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body {
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overflow: hidden;
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background: #262b2e
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}
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#canvas {
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z-index: 1;
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}
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</style>
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</head>
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<body>
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<div id="wrapper">
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<canvas id="canvas" width="1920px" height="1080px"></canvas>
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</div>
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<script>
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// min and max radius, radius threshold and percentage of filled circles
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var radMin = 10,
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radMax = 80,
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filledCircle = 30, //percentage of filled circles
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concentricCircle = 60, //percentage of concentric circles
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radThreshold = 25; //IFF special, over this radius concentric, otherwise filled
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//min and max speed to move
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var speedMin = 0.3,
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speedMax = 0.6;
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//max reachable opacity for every circle and blur effect
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var maxOpacity = 0.6;
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//default palette choice
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var colors = ['52,168,83', '117,95,147', '199,108,23', '194,62,55', '0,172,212', '120,120,120'],
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circleBorder = 10,
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backgroundLine = colors[0];
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var backgroundMlt = 0.85;
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//min distance for links
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var linkDist = Math.min(canvas.width, canvas.height) / 2.4,
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lineBorder = 2.5;
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//most importantly: number of overall circles and arrays containing them
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var maxCircles = 8;
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var points = [];
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//experimental vars
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var circleExp = 1,
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circleExpMax = 1.003,
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circleExpMin = 0.997,
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circleExpSp = 0.00004,
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circlePulse = false;
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var ctxfr = null;
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//circle class
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function Circle(background) {
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this.x = randRange(-canvas.width / 2, canvas.width / 2);
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this.y = randRange(-canvas.height / 2, canvas.height / 2);
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this.radius = hyperRange(radMin, radMax);
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this.filled = this.radius < radThreshold ? (randint(0, 100) > filledCircle ? false : 'full') : (randint(0, 100) > concentricCircle ? false : 'concentric');
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this.color = colors[randint(0, colors.length - 1)];
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this.borderColor = colors[randint(0, colors.length - 1)];
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this.opacity = 0.05;
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this.speed = randRange(speedMin, speedMax); // * (radMin / this.radius);
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this.speedAngle = Math.random() * 2 * Math.PI;
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this.speedx = Math.cos(this.speedAngle) * this.speed;
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this.speedy = Math.sin(this.speedAngle) * this.speed;
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var spacex = Math.abs((this.x - (this.speedx < 0 ? -1 : 1) * (canvas.width / 2 + this.radius)) / this.speedx),
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spacey = Math.abs((this.y - (this.speedy < 0 ? -1 : 1) * (canvas.height / 2 + this.radius)) / this.speedy);
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this.ttl = Math.min(spacex, spacey);
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}
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Circle.prototype.init = function() {
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Circle.call(this, this.background);
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};
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//support functions
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//generate random int a<=x<=b
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function randint(a, b) {
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return Math.floor(Math.random() * (b - a + 1) + a);
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}
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//generate random float
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function randRange(a, b) {
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return Math.random() * (b - a) + a;
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}
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//generate random float more likely to be close to a
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function hyperRange(a, b) {
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return Math.random() * Math.random() * Math.random() * (b - a) + a;
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}
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//rendering function
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function drawCircle(ctx, circle) {
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//circle.radius *= circleExp;
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var radius = circle.background ? circle.radius *= circleExp : circle.radius /= circleExp;
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ctx.beginPath();
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ctx.arc(circle.x, circle.y, radius * circleExp, 0, 2 * Math.PI, false);
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ctx.lineWidth = Math.max(1, circleBorder * (radMin - circle.radius) / (radMin - radMax));
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ctx.strokeStyle = ['rgba(', circle.borderColor, ',', circle.opacity, ')'].join('');
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if (circle.filled === 'full') {
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ctx.fillStyle = ['rgba(', circle.borderColor, ',', circle.opacity, ')'].join('');
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ctx.fill();
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ctx.lineWidth=0;
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ctx.strokeStyle = ['rgba(', circle.borderColor, ',', 0, ')'].join('');
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}
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ctx.stroke();
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if (circle.filled === 'concentric') {
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ctx.beginPath();
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ctx.arc(circle.x, circle.y, radius / 2, 0, 2 * Math.PI, false);
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ctx.lineWidth = Math.max(1, circleBorder * (radMin - circle.radius) / (radMin - radMax));
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ctx.strokeStyle = ['rgba(', circle.color, ',', circle.opacity, ')'].join('');
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ctx.stroke();
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}
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circle.x += circle.speedx;
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circle.y += circle.speedy;
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if (circle.opacity < maxOpacity) circle.opacity += 0.01;
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circle.ttl--;
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}
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//initializing function
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function init() {
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var canvas1 = document.getElementById('canvas');
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canvas1.width = document.documentElement.clientWidth;
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canvas1.height = document.documentElement.clientHeight;
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ctxfr = document.getElementById('canvas').getContext('2d');
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ctxfr.globalCompositeOperation = 'destination-over';
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//populating the screen
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for (var i = 0; i < maxCircles * 2; i++) points.push(new Circle(false));
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window.requestAnimationFrame(draw);
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}
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//rendering function
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function draw() {
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if (circlePulse) {
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if (circleExp < circleExpMin || circleExp > circleExpMax) circleExpSp *= -1;
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circleExp += circleExpSp;
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}
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ctxfr.clearRect(0, 0, canvas.width, canvas.height); // clear canvas
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ctxfr.save();
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ctxfr.translate(canvas.width / 2, canvas.height / 2);
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//function to render each single circle, its connections and to manage its out of boundaries replacement
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function renderPoints(ctx, arr) {
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for (var i = 0; i < arr.length; i++) {
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var circle = arr[i];
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//checking if out of boundaries
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if (circle.ttl<0) {}
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var xEscape = canvas.width / 2 + circle.radius,
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yEscape = canvas.height / 2 + circle.radius;
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if (circle.ttl < -20) arr[i].init(arr[i].background);
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//if (Math.abs(circle.y) > yEscape || Math.abs(circle.x) > xEscape) arr[i].init(arr[i].background);
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drawCircle(ctx, circle);
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}
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for (var i = 0; i < arr.length - 1; i++) {
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for (var j = i + 1; j < arr.length; j++) {
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var deltax = arr[i].x - arr[j].x;
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var deltay = arr[i].y - arr[j].y;
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var dist = Math.pow(Math.pow(deltax, 2) + Math.pow(deltay, 2), 0.5);
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//if the circles are overlapping, no laser connecting them
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if (dist <= arr[i].radius + arr[j].radius) continue;
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//otherwise we connect them only if the dist is < linkDist
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if (dist < linkDist) {
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var xi = (arr[i].x < arr[j].x ? 1 : -1) * Math.abs(arr[i].radius * deltax / dist);
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var yi = (arr[i].y < arr[j].y ? 1 : -1) * Math.abs(arr[i].radius * deltay / dist);
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var xj = (arr[i].x < arr[j].x ? -1 : 1) * Math.abs(arr[j].radius * deltax / dist);
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var yj = (arr[i].y < arr[j].y ? -1 : 1) * Math.abs(arr[j].radius * deltay / dist);
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ctx.beginPath();
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ctx.moveTo(arr[i].x + xi, arr[i].y + yi);
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ctx.lineTo(arr[j].x + xj, arr[j].y + yj);
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var samecolor = arr[i].color == arr[j].color;
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ctx.strokeStyle = ["rgba(", arr[i].borderColor, ",", Math.min(arr[i].opacity, arr[j].opacity) * ((linkDist - dist) / linkDist), ")"].join("");
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ctx.lineWidth = (arr[i].background ? lineBorder * backgroundMlt : lineBorder) * ((linkDist - dist) / linkDist); //*((linkDist-dist)/linkDist);
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ctx.stroke();
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}
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}
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}
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}
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var startTime = Date.now();
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renderPoints(ctxfr, points);
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deltaT = Date.now() - startTime;
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ctxfr.restore();
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window.requestAnimationFrame(draw);
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}
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init();
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/*Credits and aknowledgements:
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Original Idea and Design by Luca Luzzatti
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Optimizing tips from Benjamin K?stner
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General tips from Salvatore Previti*/
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</script>
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</body>
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</html>
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