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whenever user click on to get new password but doesnt fill in the username field it shows that message i have set up the server because if user put username the form works but if left blanck this error message keeps coming up

 function procForgotPass(){

      global $database, $session, $mailer, $form;

      /* Username error checking */

      $subuser = $_POST['user'];

      $field = "user";  //Use field name for username

      if(!$subuser || strlen($subuser = trim($subuser)) == 0){

         $form->setError($field, "* Username not entered<br>");

      }

      else{

         /* Make sure username is in database */

         $subuser = stripslashes($subuser);

         if(strlen($subuser) < 5 || strlen($subuser) > 30 ||

            !eregi("^([0-9a-z])+$", $subuser) ||

            (!$database->usernameTaken($subuser))){

            $form->setError($field, "* Username does not exist<br>");

         }

      }

      
      /* Errors exist, have user correct them */

      if($form->num_errors > 0){

         $_SESSION['value_array'] = $_POST;

         $_SESSION['error_array'] = $form->getErrorArray();

      }    

      /* Generate new password and email it to user */

      else

      // make sure seesion starts before

      header("Location: ".$session->referrer);

      

      {

         /* Generate new password */

         $newpass = $session->generateRandStr(8);

         

         /* Get email of user */

         $usrinf = $database->getUserInfo($subuser);

         $email  = $usrinf['email'];

         

         /* Attempt to send the email with new password */

         if($mailer->sendNewPass($subuser,$email,$newpass)){

            /* Email sent, update database */

            $database->updateUserField($subuser, "password", md5($newpass));

            $_SESSION['forgotpass'] = true;

         }

         /* Email failure, do not change password */

         else{

            $_SESSION['forgotpass'] = false;

         }

      }

      

      

   } 

PHP:

this is my mail set

 function sendNewPass($user, $email, $pass){

      $from = "From: ".EMAIL_FROM_NAME." <".EMAIL_FROM_ADDR.">";

      $subject = "Elite ticket master - Your new password";

      $body = $user.",\n\n"

             ."We've generated a new password for you at your "

             ."request, you can use this new password with your "

             ."username to log in to Eliteticketsevents Site.\n\n"

             ."Username: ".$user."\n"

             ."New Password: ".$pass."\n\n"

             ."It is recommended that you change your password "

             ."to something that is easier to remember, which "

             ."can be done by going to the My Account page "

             ."after signing in.\n\n"

             ."- EliteTickets's Site";

             

     

              $server = "smtp.virgin.net";

 ini_set("SMTP",$server);

 

 



       return mail($email,$subject,$body,$from);

PHP: