public string clFielName(string fileName)

     {

         System.Web.HttpContext curContext = System.Web.HttpContext.Current;

         string outputFileName = null;

         string browser = curContext.Request.UserAgent.ToUpper();

         if (browser.Contains("MS") == true && browser.Contains("IE") == true)

         {

             outputFileName = System.Web.HttpUtility.UrlEncode(fileName);

         }

         else if (browser.Contains("FIREFOX") == true)

         {

             outputFileName = "\"" + fileName + "\"";

         }

         else

         {

             outputFileName = System.Web.HttpUtility.UrlEncode(fileName);

         }

         return outputFileName;

     }