V3: Line with weekends marked

HTML

<script src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script src="http://www.amcharts.com/lib/3/serial.js"></script>
<div id="chartdiv" style="width: 100%; height: 342px;"></div>

JavaScript

var chart;
var chartData = [];
var chartCursor;

AmCharts.ready(function () {
    // generate some data first
    generateChartData();
    
    // SERIAL CHART    
    chart = new AmCharts.AmSerialChart();
    chart.pathToImages = "http://www.amcharts.com/lib/3/images/";
    chart.dataProvider = chartData;
    chart.categoryField = "date";
    chart.balloon.bulletSize = 5;
    
    // listen for "dataUpdated" event (fired when chart is rendered) and call zoomChart method when it happens
    chart.addListener("dataUpdated", zoomChart);
    
    // AXES
    // category
    var categoryAxis = chart.categoryAxis;
    categoryAxis.parseDates = true; // as our data is date-based, we set parseDates to true
    categoryAxis.minPeriod = "DD"; // our data is daily, so we set minPeriod to DD
    categoryAxis.gridAlpha = 0;
    categoryAxis.axisColor = "#DADADA";
    
    // value                
    var valueAxis = new AmCharts.ValueAxis();
    valueAxis.axisAlpha = 0;
    chart.addValueAxis(valueAxis);
    
    // GRAPH
    var graph = new AmCharts.AmGraph();
    graph.title = "red line";
    graph.valueField = "visits";
    graph.bullet = "round";
    graph.bulletBorderColor = "#FFFFFF";
    graph.bulletBorderThickness = 2;
    graph.bulletBorderAlpha = 1;
    graph.lineThickness = 2;
    graph.lineColor = "red";
    graph.hideBulletsCount = 50; // this makes the chart to hide bullets when there are more than 50 series in selection
    chart.addGraph(graph);
    
    // value axis used for fills
    var valueAxisColumn = new AmCharts.ValueAxis();
    valueAxisColumn.axisAlpha = 0;
    valueAxisColumn.stackType = "100%";
    valueAxisColumn.labelsEnabled = false;
    valueAxisColumn.gridAlpha = 0;
    valueAxisColumn.axisAlpha = 0;
    chart.addValueAxis(valueAxisColumn);
    
    // Collumns
    var weekendsGraph = new AmCharts.AmGraph();
    weekendsGraph.valueAxis = valueAxisColumn;
    weekendsGraph.valueField = "visits";
    weekendsGraph.alphaField = "alpha";
   ...