title: Bootstrap-select DropDownList not showing
body: <p>I have a bootstrap-select combobox that I fill with data in an ajax call
  <strong>Html:</strong></p>
  
  <pre><code>&lt;div class="row"&gt;
  &lt;select id="selectGemeente1" class="selectpicker" data-live-search="true"&gt;&lt;/select&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>Ajax call:</strong></p>
  
  <pre><code>var gemeenteLijst = [];
  
  var GetGemeentes = function () {
      $.ajax({
          type: "GET",
          dataType: "json",
          url: 'https://localhost::blabla',
          contentType: "application/json; charset=utf-8",
          success: function (data) {
              var test = document.getElementById("selectGemeente1");
              data.forEach(function (item) {
                  var opt = document.createElement("option");
                  opt.value = item.GemeenteId;
                  opt.innerHTML = item.Naam;
                  test.appendChild(opt);
              });         
          },
          error: function (xhr, status, error) {
              alert(xhr.responseText);
          }
      });
  }
  
  $(document).ready(function () {
      GetGemeentes();  
  })
  </code></pre>
  
  <p>After running my application, my select is filled but the dropdown is not opening..</p>
  
  <p><a href="http://i.stack.imgur.com/FkSqd.png" rel="nofollow">html after run</a></p>
  
  <p>I have seen a lot of solutions saying that I should put this in my $(document).ready</p>
  
  <pre><code>$(".selectpicker").html(optgroup);
  </code></pre>
  
  <p>but then I get an error saying that .selectpicker is not a function.</p>
  
  <pre><code>gemeenteLijstLaden.js:36 Uncaught TypeError: $(...).selectpicker is not a function
  </code></pre>
  
  <p>I have implemented these script files</p>
  
  <pre><code>&lt;script src="~/Scripts/jquery-2.2.3.min.js"&gt;&lt;/script&gt;
  &lt;script src="~/Scripts/bootstrap.min.js"&gt;&lt;/script&gt;
  &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.10.0/js/bootstrap-select.js"&gt;&lt;/script&gt;
  &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-select/1.10.0/js/i18n/defaults-nl_NL.min.js"&gt;&lt;/script&gt;
  &lt;script src="~/Scripts/myCharts/gemeenteLijstLaden.js"&gt;&lt;/script&gt;
  </code></pre>