URL Using Login Application in XCode

.h File

@interface login : UIViewController
{
    NSString *content;
}
-(IBAction)log:(id)sender;
-(IBAction)signup:(id)sender;
@property (retain, nonatomic) IBOutlet UITextField *UserName;
@property (retain, nonatomic) IBOutlet UITextField *Password;
@end


.m File

#import "screen2.h"
#import "Reachability.h"

@implementation login

@synthesize UserName,Password;
-(IBAction)log:(id)sender
{
    Reachability *reach = [Reachability reachabilityWithHostName:@"www.google.com"];
NetworkStatus internetStatus = [reach currentReachabilityStatus];

if ((internetStatus != ReachableViaWiFi) && (internetStatus != ReachableViaWWAN))
       {
/// Create an alert if connection doesn't work
UIAlertView *myAlert = [[UIAlertView alloc]
initWithTitle:@"No Internet Connection"   message:@""
delegate:self
cancelButtonTitle:@"Ok"
otherButtonTitles:nil];
[myAlert show];
[myAlert release];
}

 
    NSString *stringURL =[NSString stringWithFormat: @"http://www.support.iwedplanner.com/KnowledgeBowl/KnowBowl_User.aspx?UserName=%@&Password=%@",UserName.text,Password.text,nil];
    NSURL *url = [NSURL URLWithString:stringURL];
    content=[NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:NULL];
    if([content hasPrefix:@"|Invalid UserName/Password |"])
     
    {
        UIAlertView *objAlert = [[UIAlertView alloc] initWithTitle:@"Message!" message:@"Invalid UserName/Password" delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK",nil];
        [objAlert setTag:1];
        [objAlert show];
        [objAlert release];
        UserName.text=@"";
        Password.text=@"";
    }
    else
    {
        screen2 *start=[[screen2 alloc]init];
        [self.navigationController pushViewController:start animated:YES];
    }

}