title: "ReferenceError: $ is not defined " while trying to use datetimepicker
body: <p>while i am trying to use date function of bootstrap i am getting this error <strong>ReferenceError: $ is not defined</strong>
  my html code is like </p>
  
  <pre><code>&lt;div class='input-group date' id='datetimepicker1'&gt;
      &lt;label&gt;&lt;b&gt;Start Date&lt;/b&gt;
         &lt;input type='text' name="start_date" id="start_date" class="form-control" required /&gt;
      &lt;span class="input-group-addon"&gt;
          &lt;span class="glyphicon glyphicon-calendar"&gt;&lt;/span&gt;
      &lt;/span&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>i used several link in the bottom of html </p>
  
  <pre><code>&lt;!-- basic scripts --&gt;
  &lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"&gt;&lt;/script&gt;
  &lt;!--For Date Time--&gt;
  &lt;script src="js/jquery-1.7.1.js"&gt;&lt;/script&gt;  
  &lt;script src="js/bootstrap.js"&gt;&lt;/script&gt;
  &lt;script src="js/bootstrap-datepicker.js"&gt;&lt;/script&gt;
  &lt;script src="//code.jquery.com/jquery-1.10.2.js"&gt;&lt;/script&gt;
  &lt;script src="//code.jquery.com/ui/1.11.4/jquery-ui.js"&gt;&lt;/script&gt;
  &lt;link rel="stylesheet" href="//code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css"&gt;
  &lt;link rel="stylesheet" href="/resources/demos/style.css"&gt;
  </code></pre>
  
  <p>i used this datepicker and datetimepicker several time.. Sometimes they work sometime they don't...is there is any way to use date by not getting any trouble. my date picker function is like this </p>
  
  <pre><code>&lt;script type="text/javascript"&gt;
      /*$(function () {
          $('#start_date').datepicker({
              dateFormat: 'yy-mm-dd'
          });
  
          $('#end_date').datepicker({
              dateFormat: 'yy-mm-dd'
          });
      });*/
  
      $(function () {
          $('#datetimepicker1').datetimepicker({
              format: 'YYYY-MM-DD'
          });
  
          $('#datetimepicker2').datetimepicker({
              format: 'YYYY-MM-DD'
          });
      });
  &lt;/script&gt;
  </code></pre>