JSFiddle - React, Tailwind, and code Playground
by Aashish Handa
HTML
<html>
<head>
<link href="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/css/bootstrap.css" />
</head>
<body>
<div style="padding-top: 50px;"></div>
<div class="container">
<div class="row">
<div class="col-xs-6">
<select id="myDropdown" class="form-control">
<option value="">Select Month</option>
<option value="100">January</option>
<option value="150">February</option>
<option value="100">March</option>
<option value="150">April</option>
<option value="100">May</option>
<option value="150">June</option>
<option value="100">July</option>
<option value="150">August</option>
<option value="100">September</option>
<option value="150">October</option>
<option value="100">November</option>
<option value="150">December</option>
</select>
</div>
<div class="col-xs-6">
<input id="txtBox" type="text" readonly='1' class="form-control">
</div>
</div>
</div>
<script src="//cdnjs.cloudflare.com/ajax/libs/jquery/1.11.1/jquery.js"></script>
<script src="//cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.7/js/bootstrap.js"></script>
</body>
</html>
JavaScript
$("#myDropdown").change(function () {
var selectedValue = $(this).val();
$("#txtBox").val($(this).find("option:selected").attr("value"))
});