How to hire click function in Google timeline Chart

I am using Google Timeline chart and want to hire a click function. Simply when I clicked on the colored rectangles or text I want a bootstrap Modal show up.

google.charts.load("current", {packages:["timeline"]});
google.charts.setOnLoadCallback(drawChart);
function drawChart() {

var container = document.getElementById('example5.1');
var chart = new google.visualization.Timeline(container);
var dataTable = new google.visualization.DataTable();
dataTable.addColumn({ type: 'string', id: 'Room' });
dataTable.addColumn({ type: 'string', id: 'Name' });
dataTable.addColumn({ type: 'date', id: 'Start' });
dataTable.addColumn({ type: 'date', id: 'End' });
dataTable.addRows([
  [ 'Magnolia Room', 'Begiing JavaScript',       new Date(2017, 1, 30),  
new Date(2017, 2, 30) ],
  [ 'Learning for Life', 'Intermediate JavaScript',    new Date(2017, 3, 1),  
new Date(2017, 4, 30) ],
  [ 'Magnolia Room', 'Advanced JavaScript',        new Date(2017, 5, 01),  
new Date(2017, 6, 30) ],
  [ 'Willow Room',   'Begiing Google Charts',    new Date(2017, 1, 30), 
new Date(2017, 3, 30) ],
  [ 'Willow Room',   'Intermediate Google Charts', new Date(2017, 4, 30), 
new Date(2017, 5, 30) ],
  [ 'Willow Room',   'Advanced Google Charts',     new Date(2017, 6, 30), 
new Date(2018, 1, 30) ]]);

var options = {
timeline: { colorByRowLabel: true }
};

chart.draw(dataTable, options);
}

Please take a look at this Fiddle

please help.