title: ASP.net dropdown list postback dosnot work inside jquery and control panel
body: <p>I call an asp webpage inside JQuery  code as following :</p>
  
  <pre><code>$("#zr_users_edit").click(function () {
          $("#panel-label").text("Edit User Account")
          $("#display-panel").stop().animate({ left: 0 }, 400);
          $("#data-panel").load("index.aspx?ref=users&amp;acts=edit", {}, function (data) {
          });
      });
  </code></pre>
  
  <p>the webpage contains a dropdownlist with auto postback option , when i click and browse it on IE11 i got the following error message : </p>
  
  <blockquote>
    <p>Unable to get property 'length' of undefined or null reference</p>
  </blockquote>
  
  <p>the page code as following :</p>
  
  <pre><code>&lt;form id="form1" runat="server"&gt;
      &lt;asp:ScriptManager ID = "ScriptManager1" OnAsyncPostBackError="ScriptManager1_AsyncPostBackError" runat="server" &gt;&lt;/asp:ScriptManager&gt;
      &lt;asp:UpdatePanel ID = "UpdatePanel1" runat="server"&gt;
          &lt;ContentTemplate&gt;
              &lt;asp:Label ID="zr_lb_message" runat="server" Text=" " style="color:Red;padding-left:35%;"&gt;&lt;/asp:Label&gt;
              &lt;div id ="zr_htm_add" runat="server" visible="False"  style="display:table;float:left;padding-left:35%;margin-right:90px;"&gt;
                  &lt;br /&gt;
                  &lt;div class= "div-row" id="zr_htm_edit" runat="server" visible="False"&gt;
                      &lt;div class="div-cell"&gt;
                          &lt;asp:DropDownList ID="zr_dl_users" runat="server"  AutoPostBack="True" class="dynamicDropDownList" style="width: 119px"&gt;
                              &lt;asp:ListItem Value="-1"&gt;Select User:&lt;/asp:ListItem&gt;
                          &lt;/asp:DropDownList&gt;
                      &lt;/div&gt;
                  &lt;/div&gt;&lt;/ContentTemplate&gt;&lt;/asp:UpdatePanel&gt;&lt;/form&gt;                 
  </code></pre>
  
  <p>so is there some thing i missed to do , please help me </p>