title: Google chart visualisation example does not work
body: <p>In this offical google example I replaced the url getData.php by a valid internet url. The url works fine, when I use it in any browser address bar.
  It delivers a valid json representation of a google DataTable Type.
  When I use it in the script below, nothing happens. I only get an empty browser page.
  What could be the problem?
  My URL looks like:
  <a href="https://alpenegg.hopto.org/LorawanBackend/lorawan/sensorservice/5" rel="nofollow noreferrer">https://alpenegg.hopto.org/LorawanBackend/lorawan/sensorservice/5</a>
  The server is expecting a GET Method.</p>
  
  <pre><code>&lt;html&gt;
    &lt;head&gt;
      &lt;!--Load the AJAX API--&gt;
      &lt;script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript"&gt;
  
      // Load the Visualization API and the piechart package.
      google.charts.load('current', {'packages':['corechart']});
  
      // Set a callback to run when the Google Visualization API is loaded.
      google.charts.setOnLoadCallback(drawChart);
  
      function drawChart() {
        var jsonData = $.ajax({
            url: "getData.php",
            dataType: "json",
            async: false
            }).responseText;
  
        // Create our data table out of JSON data loaded from server.
        var data = new google.visualization.DataTable(jsonData);
  
        // Instantiate and draw our chart, passing in some options.
        var chart = new google.visualization.PieChart(document.getElementById('chart_div'));
        chart.draw(data, {width: 400, height: 240});
      }
  
      &lt;/script&gt;
    &lt;/head&gt;
  
    &lt;body&gt;
      &lt;!--Div that will hold the pie chart--&gt;
      &lt;div id="chart_div"&gt;&lt;/div&gt;
    &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>