title: How to populate a drop down with values from JavaScript?
body: <p>I added a button to the ribbon toolbar button in my extension to the Tridion CMS. On click of the button a popup page will display with two drop downs. By changing the values in the first drop down control I should populate the values for second drop down control. In my case I am using <code>ASP drop down list</code> control. For the time being I will hard code the values to be populated to the second drop down in java script. For this requirement I am using the following code but I am not able to populate the value (Not Identifying the  tag).</p>
  
  <p>Java script code:</p>
  
  <pre><code>ABC.WCMS.RTFExtension.Popups.ButtonPopup.prototype._populate = function () {    
      var selectedValue = $('#functionalcomponent').value;//First dropdown selected value
      var dropdownId = $("#Dd");//Second Dropdown Control
  
          switch (selectedValue) {
  
              case "Home Ware":
                  dropdownId.append($("&lt;option&gt; &lt;/option&gt;").val("Select Sub-Category").html(""));
                  dropdownId.append($("&lt;option&gt; &lt;/option&gt;").val("Air-Conditioners/Coolers").html("Air-Conditioners/Coolers"));              
                  break;
              case "Education":
                  dropdownId.append($("&lt;option&gt; &lt;/option&gt;").val("Select Sub-Category").html(""));
                  dropdownId.append($("&lt;option&gt; &lt;/option&gt;").val("Colleges").html("Colleges"));
                  break;
              default:
                  dropdownId.append($("&lt;option&gt; &lt;/option&gt;").val("Select Sub-Category").html(""));
                  dropdownId.append($("&lt;option&gt; &lt;/option&gt;").val("No Value").html("No Value"));
  
          }
      return true;
  }
  </code></pre>
  
  <p>ASPX Controls:</p>
  
  <pre><code>&lt;%--Dropdown1--%&gt;
  &lt;asp:DropDownList ID="functionalcomponent" runat="server"&gt;&lt;/asp:DropDownList&gt;
  &lt;%--Dropdown2--%&gt;
  &lt;asp:DropDownList ID="Dd" runat="server"&gt;&lt;/asp:DropDownList&gt;
  </code></pre>
  
  <p>How can I populate the values for second drop down from external JavaScript file?</p>