ASP.NET

byte[] data = (byte[])Dt.Rows[0]["documentBinary"];
                   // encoding.GetBytes(Dt.Rows[0]["documentBinary"].ToString());// (byte[])Dt.Rows[0]["documentBinary"].ToString();

                System.Web.HttpResponse response = System.Web.HttpContext.Current.Response;
                response.ClearHeaders();
                response.ClearContent();
                response.Clear();
                //response.AddHeader("Content-Type", Dt.Rows[0]["documentContentType"].ToString());
                response.ContentType = Dt.Rows[0]["documentContentType"].ToString();
                response.AppendHeader("Content-Disposition",
                    "attachment; filename=" + Dt.Rows[0]["titel"].ToString() + ".pdf; size=" + data.Length.ToString());

                response.BinaryWrite(data);
                response.Flush();
                response.End();

function btnAddEmail_onclick() {

    var cbCCEmails = document.getElementById("cbCCEmails");    
    var dropUserEmails = document.getElementById("<%= dropUserEmails.ClientID %>");
    
    var SelectedIndex = dropUserEmails.selectedIndex;
    var Email = dropUserEmails(SelectedIndex).value;
    var Name = dropUserEmails(SelectedIndex).text;
    
    if (SelectedIndex != -1)
    {
        cbCCEmails.options.add(new Option(Email, Name));
        dropUserEmails.remove(SelectedIndex);
    }
}

for (int i = 0; i < cbCCEmails.Items.Count; i++)
            {
                if (String.IsNullOrEmpty(CCEmails))
                    CCEmails = cbCCEmails.Items[i].Text;
                else
                    CCEmails += "," + cbCCEmails.Items[i].Text;

                mm.CC.Add(new MailAddress(cbCCEmails.Items[i].Text));
            }

window.open(url, 'Download', 'height=1,width=1,top=0,left=-1000');