Geochar Bug - Listener in iOS

HTML

<script src="//www.google.com/jsapi"></script>
<div id="visualization"></div>

JavaScript

google.load('visualization', '1.1', {packages: ['geochart'], callback: drawVisualization});

function drawVisualization() {
    
 var data = new google.visualization.DataTable();
    
 data.addColumn('string', 'Country');
 data.addColumn('number', 'Value'); 
    data.addColumn({type: 'string', role: 'tooltip', 'p': {'html': true}});

 data.addRows([[{v:'US',f:'United States of America'},0,'21% of <strong> Visits</strong>']]);
 data.addRows([[{v:'GB',f:'United Kingdom'},1,'7% of visits']]);
 data.addRows([[{v:'DE',f:'Germany'},2,'6% of visits']]);
 data.addRows([[{v:'FR',f:'France'},3,'5% of visits']]);

  var geochart = new google.visualization.GeoChart(
      document.getElementById('visualization'));
    
    google.visualization.events.addListener(geochart, 'select', function() {
              alert('A region was clicked');
  });
    
    var options = {
    tooltip: {isHtml: false},
    legend: 'none',
    tooltip: {trigger:'selection'}
  };
    
    geochart.draw(data, options);
}