<link href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/css/bootstrap.min.css" rel="stylesheet" id="bootstrap-css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.0/js/bootstrap.min.js"></script>
<script src="//code.jquery.com/jquery-1.11.1.min.js"></script>
<div class="container">
<div class="row">
<h2>Javascript Select and Change</h2>
<form>
<div class="dropdown">
<select class="dropdown-select-version select" name="options">
<option> Architecture </option><option value="x86">x86</option>
<option value="x64">x64</option>
</select>
</div>
<a class="btn btn-block btn-success download-target" title="Download" href="#" alt="Download">Download</a>
</form>
</div>
</div>