firing ASP.NET Events from javascript

<script language="javascript">
      function AjaxCallback_Success(objAjax) {
        if (objAjax.responseText == "refresh") {
                document.getElementById('<%= btnHidden.ClientID %>').click();
         }
      }
    </script>
    <asp:UpdatePanel ID="upStatus" runat="server">
    <ContentTemplate>
<asp:Button ID="btnHidden" runat="server" style="display: none;" OnClick="SomeMethod" />
    <asp:DropDownList ID="ddlStatus" field="Orders_Status" parent="Orders" runat="server">
    </asp:DropDownList>
    </ContentTemplate>
    </asp:UpdatePanel>

__doPostBack('eventTarget','eventArguments');

__doPostBack('<%= btnHidden.ClientID %>','');