I have tried lots of examples given in this type of questions but still can't find how to display selected item on the title of the bootstrap dropdown list and how to get the selected item through javascript. if someone know the code please help me with the links that I should include in the head section. Because I think it may be I missing something in the head section. here is sample dropdown list.
<div class="btn-group">
<button type="button" class="btn btn-default dropdown-toggle" data-toggle="dropdown">
Option: <span class="selection">Option 1</span><span class="caret"></span>
</button>
<ul class="dropdown-menu" role="menu">
<li><a href="#">Option 1</a></li>
<li><a href="#">Option 2</a></li>
<li><a href="#">Option 3</a></li>
</ul>
</div>