title: dropdownlist not changed SelectedValue on server side
body: <p>I have an dropdownlist</p>
  
  <pre><code>&lt;asp:DropDownList ID="ddlNationality" runat="server" ClientIDMode="Static"&gt;
                                  &lt;/asp:DropDownList&gt;
  </code></pre>
  
  <p>in document ready I set</p>
  
  <pre><code>ddlNationality.selectedIndex = -1;
  </code></pre>
  
  <p>for show to user nothing selected </p>
  
  <p>After I change value and click some button on server side my selected value is alway zero, after I change selected value in javascript I check if selected values is changed and all i ok, but o server side selected value not changed,.. how to proceed?</p>
  
  <p>I can to insert in this dropdownlist first item with no value and no text, but I want to have in dropdownlist only my values without clear field</p>