Google Charts Basic Calendar Chart

Google Charts Basic Calendar Chart

<html>
   <head>
      <title>Google Charts Tutorial</title>
      <script type = "text/javascript" src = "https://www.gstatic.com/charts/loader.js">
      </script>
      <script type = "text/javascript">
         google.charts.load('current', {packages: ['corechart','calendar']});     
      </script>
   </head>

   <body>
      <div id = "container" style = "width: 550px; height: 400px; margin: 0 auto">
      </div>
      <script language = "JavaScript">
         function drawChart() {
            // Define the chart to be drawn.
            var data = new google.visualization.DataTable();
            data.addColumn({ type: 'date', id: 'Date' });
            data.addColumn({ type: 'number', id: 'Students' });
            data.addRows([
               [ new Date(2012, 3, 13), 50 ],
               [ new Date(2012, 3, 14), 50 ],
               [ new Date(2012, 3, 15), 49 ],
               [ new Date(2012, 3, 16), 48 ],
               [ new Date(2012, 3, 17), 50 ],

               [ new Date(2012, 4, 1), 50 ],
               [ new Date(2012, 4, 2), 50 ],
               [ new Date(2012, 4, 3), 49 ],
               [ new Date(2012, 4, 4), 48 ],
               [ new Date(2012, 4, 5), 50 ],

               [ new Date(2012, 5, 4), 40 ],
               [ new Date(2012, 5, 5), 50 ],
               [ new Date(2012, 5, 10), 48 ],
               [ new Date(2012, 5, 11), 50 ],
               [ new Date(2012, 5, 12), 42 ],
               [ new Date(2012, 5, 20), 45 ],
               [ new Date(2012, 5, 21), 46 ],
               [ new Date(2012, 5, 29), 45 ],

               [ new Date(2013, 3, 13), 40 ],
               [ new Date(2013, 3, 14), 40 ],
               [ new Date(2013, 3, 15), 39 ],
               [ new Date(2013, 3, 16), 38 ],
               [ new Date(2013, 3, 17), 40 ],

               [ new Date(2013, 4, 1), 40 ],
               [ new Date(2013, 4, 2), 40 ],
               [ new Date(2013, 4, 3), 49 ],
               [ new Date(2013, 4, 4), 48 ],
               [ new Date(2013, 4, 5), 40 ],

               [ new Date(2013, 5, 4), 40 ],
               [ new Date(2013, 5, 5), 50 ],
               [ new Date(2013, 5, 12), 48 ],
               [ new Date(2013, 5, 13), 40 ],
               [ new Date(2013, 5, 19), 32 ],
               [ new Date(2013, 5, 23), 45 ],
               [ new Date(2013, 5, 24), 36 ],
               [ new Date(2013, 5, 30), 45 ]
            ]);


            // Set chart options
            var options = {'title':'Attendence', 'width':550, 'height':400};

            // Instantiate and draw the chart.
            var chart = new google.visualization.Calendar(document.getElementById('container'));
            chart.draw(data, options);
         }
         google.charts.setOnLoadCallback(drawChart);
      </script>
   </body>
</html>