Implement Cascading jQuery AutoComplete in ASP.Net

hi

i am using autocomplete for category but i want to filter the category based on city, so i need to pass two value to http handler from jquery, below code is used for passing single value.

<script type="text/javascript">     $(document).ready(function() {         $("#<%=txtcategory.ClientID%>").autocomplete('searchcategory.ashx');                });        </script>

Http handler Code

<%@ WebHandler Language="C#" Class="searchcategory" %>

using System;
using System.Web;
using System.Data.SqlClient;
using System.Configuration;
using System.Text;

public class searchcategory : IHttpHandler {
    
    public void ProcessRequest (HttpContext context) {
      string prefixText = context.Request.QueryString["q"];
        using (SqlConnection conn = new SqlConnection())
        {
            conn.ConnectionString = ConfigurationManager.ConnectionStrings["yaazaaconnstring"].ToString();

            using (SqlCommand cmd = new SqlCommand())
            {
                cmd.CommandText = "select distinct(sub_cat_name) as bus_name  from contracts where " +
               "sub_cat_name like @SearchText + '%'" +
               " union select distinct(cat_name) as bus_name from contracts where " +
               "cat_name like @SearchText + '%'";
                cmd.Parameters.AddWithValue("@SearchText", prefixText);
                cmd.Connection = conn;
                StringBuilder sb = new StringBuilder();
                conn.Open();
                using (SqlDataReader sdr = cmd.ExecuteReader())
                {
                    while (sdr.Read())
                    {
                        sb.Append(sdr["bus_name"])
                            .Append(Environment.NewLine);
                    }
                }
                conn.Close();
                context.Response.Write(sb.ToString());
            }
        }
    }
 
    public bool IsReusable {
        get {
            return false;
        }
    }

}