Ios WEb Service Communication

    I am calling this web-service for test purpose and it is working fine.
    <?php

    header('Content-type: application/json');
    if($_POST) {
        if($_POST['email'] == 'saad.bsit@hotmail.com' && $_POST['password'] == '12345') {
        echo '{"success":1}';
     } else {
        echo '{"success":0,"error_message":"Username and/or password is invalid."}';
    }
    }else {    echo '{"success":0,"error_message":"Username and/or password is invalid."}';}
    ?>

    action on button in sign in page
    - (IBAction)btnSignIn:(id)sender {
      @try {

            if([[txtUserEmail text] isEqualToString:@""] || [[txtUserPassword text] isEqualToString:@""] ) {
                [self alertStatus:@"Please enter both Username and Password" :@"Login Failed!"];
            } else {
                NSString *post =[[NSString alloc] initWithFormat:@"email=%@&password=%@",[txtUserEmail text],[txtUserPassword text]];
                NSLog(@"PostData: %@",post);

                NSURL *url=[NSURL URLWithString:@"http://localhost/colorSearch/sample_code.php"];

                NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

                NSString *postLength = [NSString stringWithFormat:@"%d", [postData length]];

                NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
                [request setURL:url];
                [request setHTTPMethod:@"POST"];
                [request setValue:postLength forHTTPHeaderField:@"Content-Length"];
                [request setValue:@"application/json" forHTTPHeaderField:@"Accept"];
                [request setValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];
                [request setHTTPBody:postData];

                //[NSURLRequest setAllowsAnyHTTPSCertificate:YES forHost:[url host]];

                NSError *error = [[NSError alloc] init];
                NSHTTPURLResponse *response = nil;
                NSData *urlData=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];

                NSLog(@"Response code: %d", [response statusCode]);
                if ([response statusCode] >=200 && [response statusCode] <300)
                {
                    NSString *responseData = [[NSString alloc]initWithData:urlData encoding:NSUTF8StringEncoding];
                    NSLog(@"Response ==> %@", responseData);

                    SBJsonParser *jsonParser = [SBJsonParser new];
                    NSDictionary *jsonData = (NSDictionary *) [jsonParser objectWithString:responseData error:nil];
                    NSLog(@"%@",jsonData);
                    NSInteger success = [(NSNumber *) [jsonData objectForKey:@"success"] integerValue];
                    NSLog(@"%d",success);
                    if(success == 1)
                    {
                        NSLog(@"Login SUCCESS");
                        [self alertStatus:@"Logged in Successfully." :@"Login Success!"];
                               ColorPickerViewController *cpvc =[[ColorPickerViewController alloc] init];
                               [self.navigationController pushViewController:cpvc animated:YES];

                    } else {

                        NSString *error_msg = (NSString *) [jsonData objectForKey:@"error_message"];
                        [self alertStatus:error_msg :@"Login Failed!"];
                    }

                } else {
                    if (error) NSLog(@"Error: %@", error);
                    [self alertStatus:@"Connection Failed" :@"Login Failed!"];
                }
            }
        }
        @catch (NSException * e) {
            NSLog(@"Exception: %@", e);
            [self alertStatus:@"Login Failed." :@"Login Failed!"];
        }




    }
    - (void) alertStatus:(NSString *)msg :(NSString *)title
    {
        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title
                                                            message:msg
                                                           delegate:self
                                                  cancelButtonTitle:@"Ok"
                                                  otherButtonTitles:nil, nil];

        [alertView show];
    }

    But if I try this which is the actual one code the code didn't execute. I think web service is not getting proper UrlRequest. This web service is working on tags, which I think is missing in my Request, My friend is using the same in Android and it is working fine for him, So in IOS how can we use this.
In very beginning few lines you will get my point so I think there is no need to look all below code.

    Actual Web-service.


    <?php

    /**
    PHP API for Login, Register, Changepassword, Resetpassword Requests and for Email Notifications.
    **/

    if (isset($_POST['tag']) && $_POST['tag'] != '') {
       // Get tag
       $tag = $_POST['tag'];

       // Include Database handler
       require_once 'include/DB_Functions.php';
       $db = new DB_Functions();
       // response Array
       $response = array("tag" => $tag, "success" => 0, "error" => 0);

       // check for tag type
       if ($tag == 'login') {
           // Request type is check Login
           $email = $_POST['email'];
           $password = $_POST['password'];

           // check for user
           $user = $db->getUserByEmailAndPassword($email, $password);
           if ($user != false) {
               // user found

               // echo json with success = 1
               $response["success"] = 1;
               $response["user"]["fname"] = $user["firstname"];
               $response["user"]["lname"] = $user["lastname"];
               $response["user"]["email"] = $user["email"];
       $response["user"]["uname"] = $user["username"];
               $response["user"]["uid"] = $user["unique_id"];
               $response["user"]["created_at"] = $user["created_at"];

               echo json_encode($response);
           } else {
               // user not found
               // echo json with error = 1
               $response["error"] = 1;
               $response["error_msg"] = "Incorrect email or password!";
               echo json_encode($response);

           }
       }
     else if ($tag == 'chgpass'){
     $email = $_POST['email'];

     $newpassword = $_POST['newpas'];


     $hash = $db->hashSSHA($newpassword);
           $encrypted_password = $hash["encrypted"]; // encrypted password
           $salt = $hash["salt"];
     $subject = "Change Password Notification";
            $message = "Hello User,\n\nYour Password is sucessfully changed.\n\nRegards,\nDigitalnet Team.";
             $from = "contact@Digitalnet.com";
             $headers = "From:" . $from;
    if ($db->isUserExisted($email)) {

    $user = $db->forgotPassword($email, $encrypted_password, $salt);
    if ($user) {
            $response["success"] = 1;
             mail($email,$subject,$message,$headers);
            echo json_encode($response);
    }
    else {
    $response["error"] = 1;
    echo json_encode($response);
    }


               // user is already existed - error response


           }
              else {

               $response["error"] = 2;
               $response["error_msg"] = "User not exist";
                echo json_encode($response);

    }
    }
    else if ($tag == 'forpass'){
    $forgotpassword = $_POST['forgotpassword'];

    $randomcode = $db->random_string();


    $hash = $db->hashSSHA($randomcode);
           $encrypted_password = $hash["encrypted"]; // encrypted password
           $salt = $hash["salt"];
     $subject = "Password Recovery";
            $message = "Hello User,\n\nYour Password is sucessfully changed. Your new Password is $randomcode . Login with your new Password and change it in the User Panel.\n\nRegards,\nLearn2Crack Team.";
             $from = "contact@Digitalnet.com";
             $headers = "From:" . $from;
    if ($db->isUserExisted($forgotpassword)) {

    $user = $db->forgotPassword($forgotpassword, $encrypted_password, $salt);
    if ($user) {
            $response["success"] = 1;
             mail($forgotpassword,$subject,$message,$headers);
            echo json_encode($response);
    }
    else {
    $response["error"] = 1;
    echo json_encode($response);
    }


               // user is already existed - error response


           }
              else {

               $response["error"] = 2;
               $response["error_msg"] = "User not exist";
                echo json_encode($response);
                  echo '{"success":0,"error_message":"Username and/or password is invalid."}';

    }

    }
    else if ($tag == 'register') {
           // Request type is Register new user
           $fname = $_POST['fname'];
    $lname = $_POST['lname'];
           $email = $_POST['email'];
    $uname = $_POST['uname'];
           $password = $_POST['password'];



             $subject = "Registration";
            $message = "Hello $fname,\n\nYou have sucessfully registered to our service.\n\nRegards,\nAdmin.";
             $from = "contact@Digitalnet.com";
             $headers = "From:" . $from;

           // check if user is already existed
           if ($db->isUserExisted($email)) {
               // user is already existed - error response
               $response["error"] = 2;
               $response["error_msg"] = "User already existed";
               echo json_encode($response);
           }
              else if(!$db->validEmail($email)){
               $response["error"] = 3;
               $response["error_msg"] = "Invalid Email Id";
               echo json_encode($response);
    }
    else {
               // store user
               $user = $db->storeUser($fname, $lname, $email, $uname, $password);
               if ($user) {
                   // user stored successfully
               $response["success"] = 1;
               $response["user"]["fname"] = $user["firstname"];
               $response["user"]["lname"] = $user["lastname"];
               $response["user"]["email"] = $user["email"];
       $response["user"]["uname"] = $user["username"];
               $response["user"]["uid"] = $user["unique_id"];
               $response["user"]["created_at"] = $user["created_at"];
                  mail($email,$subject,$message,$headers);

                   echo json_encode($response);
               } else {
                   // user failed to store
                   $response["error"] = 1;
                   $response["error_msg"] = "JSON Error occured in Registartion";
                   echo json_encode($response);
               }
           }
       } else {
            $response["error"] = 3;
            $response["error_msg"] = "JSON ERROR";
           echo json_encode($response);
       }
    } else {
       echo "Digitalnet API";
    }
    ?>