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function renderSignalChart(elementClass) {
    var elements = document.querySelectorAll("." + elementClass);
    if (!elements) {
        return false;
    }
    for (var i = 0; i < elements.length; i++) {
        var points = elements[i].querySelector("input"),
            canvas = elements[i].querySelector("canvas"),
            t = 0,
            context, pointsCount, step, width, height, middleline, min, max, middleHeigh, equator, colors = {};
        colors.bg = {};
        colors.bg.red = '#fee8e8';
        colors.bg.blue = '#e8f4fe';
        colors.line = {};
        colors.line.red = '#ff0000';
        colors.line.blue = '#00afef';
        width = elements[i].clientWidth - 4;
        height = elements[i].clientHeight - 4;
        middleHeigh = height / 2;
 
        points = points.value.split(",");
        points.shift();
        pointsCount = points.length;
 
        min = points.min();
        max = points.max();
 
        middleline = (max + min) / 2;
 
        oneStepY = middleHeigh / (max - middleline);
        step = width / pointsCount;
 
        equator = middleHeigh + oneStepY * middleline;
        context = canvas.getContext("2d");
 
        function createPointsCoord() {
            for (t; t < pointsCount; t++) {
                points[t] = {
                    x: t * step,
                    y: (middleHeigh - (points[t] - middleline) * oneStepY)
                };
            }
        }
        createPointsCoord();
 
        function quadraticBezier(p1, p2, p3, t) {
            return t * (t * (p3 - p2 * 2 + p1) + 2 * (p2 - p1)) + p1;
        }
 
        context.beginPath();
        context.lineWidth = 2;
        context.strokeStyle = points[1].y > equator ? colors.line.red : colors.line.blue;
        context.fillStyle = points[1].y > equator ? colors.bg.red : colors.bg.blue;
        context.moveTo(points[0].x, points[0].y);
        var exit = false,
            liney = 0;
 
        for (t = 1; t < points.length - 2; t++) {
 
            var xc = (points[t].x + points[t + 1].x) / 2;
            var yc = (points[t].y + points[t + 1].y) / 2;
 
 
            liney++;