How to pass multiple Parameter to Handler from aspx page through jquery Uploadify plugin

How to pass multiple Parameters to Handler from aspx page through jquery function using asp.net, c#. My code is given below: 

<table>

<tr>
     <td> <asp:DropDownList ID="ddlCategory" runat="server"></asp:DropDownList><span id="spnCategory" class="err" /> 
     </td>
  </tr>
  <tr>
<td>
<asp:FileUpload ID="FileUpload1" runat="server" />&nbsp;<span id="spnImage1" class="err" /> <br /><br />
     <a href="javascript:$('#<%=FileUpload1.ClientID%>').fileUploadStart()">Start Upload</a>&nbsp; 
      </td>
  </tr>

</table> 

<script type = "text/javascript">
$(window).load(
    function() {
    $("#<%=FileUpload1.ClientID %>").fileUpload({
        'uploader': 'scripts/uploader.swf',
        'cancelImg': 'images/cancel.png',
        'buttonText': 'Browse Files',
        'script': 'Upload.ashx',
        'folder': 'uploads',
        'fileDesc': 'Image Files',
        'fileExt': '*.jpg;*.jpeg;*.gif;*.png',
        'multi': true,
        'auto': true
    });
   }
);
</script>  

In the above jquery function, only FileUpload values are passing from aspx page to handler. I also want to pass the "ddlCategory.SelectedItem.Value" to Handler( Upload.ashx) and access it on handler page.How i will do it, please suggest me.