My vf Page-

<apex:page sidebar="false" standardStylesheets="false" showHeader="false">
<apex:includeScript value="https://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"/>
    <apex:includeScript value="https://ajax.googleapis.com/ajax/libs/jqueryui/1.10.1/jquery-ui.min.js"/>

    <apex:includeScript value="{!URLFOR($Resource.bootstrap, 'bootstrap/js/bootstrap.js')}"/>
    <apex:includeScript value="{!URLFOR($Resource.bootstrap, 'bootstrap/js/bootstrap.min.js')}"/>
 
    <apex:stylesheet value="{!URLFOR($Resource.bootstrap, 'bootstrap/css/bootstrap.css')}"/>
    <apex:stylesheet value="{!URLFOR($Resource.bootstrap, 'bootstrap/css/bootstrap.min.css')}"/>
 
  
     <link href="//getbootstrap.com/examples/signin/signin.css" rel="stylesheet" media="screen"/>
   


<!-- Button trigger modal -->
<button class="btn btn-primary btn-lg" data-toggle="modal" data-target="#myModal">
  Launch demo modal
</button>

<!-- Modal -->
<div class="modal fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
  <div class="modal-dialog">
    <div class="modal-content">
      <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal"><span aria-hidden="true">&times;</span><span class="sr-only">Close</span></button>
        <h4 class="modal-title" id="myModalLabel">Modal title</h4>
      </div>
      <div class="modal-body">
        ...
      </div>
      <div class="modal-footer">
        <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
        <button type="button" class="btn btn-primary">Save changes</button>
      </div>
    </div>
  </div>
</div>
</apex:page>