Your error clearly says that your dp.datepicker function is not available and you are trying to use it. Only cause of this kind of issue is you are not including the reference of bootstrap-datepicker.js file. Apart from that you need to use Jquery and bootstrap plugin too.
And the order of reference of these file should be in correct manner :
<!--
<script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.js"></script>
<!--
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.0.2/css/bootstrap.min.css" />
<!--
<link rel="stylesheet" href="//netdna.bootstrapcdn.com/bootstrap/3.0.2/css/bootstrap-theme.min.css" />
<!--
<script src="//netdna.bootstrapcdn.com/bootstrap/3.0.2/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="css/datepicker.css" type="text/css" />
<script src="Scripts/bootstrap-datepicker.js" type="text/javascript"></script>
Reference :
Click here[
^]
Good luck.