you removed the jquery-ui.min.js line
<script src="//ajax.googleapis.com/ajax/libs/jqueryui/1/jquery-ui.min.js"></script>
this code:
<link type="text/css" href="../webassist/datepicker/order_datepicker_1/jquery-ui.css" rel="stylesheet" />
<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
should be:
<link type="text/css" href="../webassist/datepicker/order_datepicker_1/jquery-ui.css" rel="stylesheet" />
<script src="//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js"></script>
<script src="//ajax.googleapis.com/ajax/libs/jqueryui/1/jquery-ui.min.js"></script>