<!DOCTYPE html>
<html>

<head>
  <link data-require="bootstrap-css@3.1.1" data-semver="3.1.1" rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css" />
  <script data-require="jquery@*" data-semver="2.1.1" src="//cdnjs.cloudflare.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
  <script data-require="bootstrap@*" data-semver="3.1.1" src="//netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
  <link rel="stylesheet" href="style.css" />
  <script src="script.js"></script>
</head>

<body>
  <h1>Hello Plunker!</h1>
  <div id="aBtnGroup" class="btn-group">
    <button type="button" value="L" class="btn btn-default">Left</button>
    <button type="button" value="M" class="btn btn-default">Middle</button>
    <button type="button" value="R" class="btn btn-default">Right</button>
  </div>
  <p>
  <div>Selected Val:  <span id="selectedVal"></span></div>
</body>

</html>
// Code goes here

$(document).ready(function() {
  
  // Get click event, assign button to var, and get values from that var
  $('#aBtnGroup button').on('click', function() {
    var thisBtn = $(this);
    
    thisBtn.addClass('active').siblings().removeClass('active');
    var btnText = thisBtn.text();
    var btnValue = thisBtn.val();
    console.log(btnText + ' - ' + btnValue);
    
    $('#selectedVal').text(btnValue);
  });
  
  // You can use this to set default value
  // It will fire above click event which will do the updates for you
  $('#aBtnGroup button[value="M"]').click();
});
/* Styles go here */