- (IBAction)login:(id)sender {

    NSInteger success = 0;
    @try {

    if([[self.txtEmail text] isEqualToString:@""] || [[self.txtPassword text] isEqualToString:@""] ) {

        [self alertStatus:@"Please enter Email and Password" :@"Sign in Failed!" :0];

    } else {
        NSString *post =[[NSString alloc] initWithFormat:@"username=%@&password=%@",[self.txtEmail text],[self.txtPassword text]];
        NSLog(@"PostData: %@",post);

        NSURL *url=[NSURL URLWithString:@"http://repayment.tk/login.php"];

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

        NSString *postLength = [NSString stringWithFormat:@"%lu", (unsigned long)[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: %ld", (long)[response statusCode]);

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

            NSError *error = nil;
            NSDictionary *jsonData = [NSJSONSerialization
                                      JSONObjectWithData:urlData
                                      options:NSJSONReadingMutableContainers
                                      error:&error];

            success = [jsonData[@"success"] integerValue];
            NSLog(@"Success: %ld",(long)success);

            if(success == 1)
            {
                NSLog(@"Login SUCCESS");
            } else {

                NSString *error_msg = (NSString *) jsonData[@"error_message"];
                [self alertStatus:error_msg :@"Sign in Failed!" :0];
            }

        } else {
            //if (error) NSLog(@"Error: %@", error);
            [self alertStatus:@"Connection Failed" :@"Sign in Failed!" :0];
        }
    }
}
@catch (NSException * e) {
    NSLog(@"Exception: %@", e);
    [self alertStatus:@"Sign in Failed." :@"Error!" :0];
}
if (success) {
    [self performSegueWithIdentifier:@"login_success" sender:self];
}
}

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

<?php
error_reporting(E_ALL ^ E_DEPRECATED);
ob_start();
$host="MYHOSTNAME"; // Host name
$username="DB USERNAME"; // Mysql username
$password="DB PASSWORD"; // Mysql password
$db_name="DB NAME"; // Database name
$tbl_name="Users"; // Table name


// Connect to server and select database.

$connect = @mysql_connect($host, $username, $password) or die (@mysql_error());
echo "Connected to MySQL";
$selectdb = @mysql_select_db($db_name, $connect,$tbl_name) or die (@mysql_error());
echo "Connected to Database";
//mysql_select_db($db_name,$tbl_name) or die(mysql_error());


// Define $username and $password
$username=$_POST['username'];
$password=md5($_POST['password']);


// To protect MySQL injection (more detail about MySQL injection)
//$username = stripslashes($username);
//$password = stripslashes($password);
//$username = mysql_real_escape_string($username);
//$password = mysql_real_escape_string($password);

$sql="SELECT * FROM $tbl_name WHERE username='$username' and password='$password'";
$result=mysql_query($sql);
echo "returned $result";
// Mysql_num_row is counting table row
$count=mysql_num_rows($result);
// If result matched $username and $password, table row must be 1 row
if ($count=="1") {
   echo '{"success":1}';
} else {
echo "Unsuccessful! $count";
}

ob_end_flush();




 ?>