title: How to send Asynchronous URL Request?
body: <p>I would like to know how do I get a return value 1 or 0 only.... back from an URL request asynchronously.</p>
  
  <p>currently I do it in this way:</p>
  
  <pre><code>NSString *UTCString = [NSString stringWithFormat:@"http://web.blah.net/question/CheckQuestions?utc=%0.f",[lastUTCDate timeIntervalSince1970]];
  NSLog(@"UTC String %@",UTCString);
  NSURL *updateDataURL = [NSURL URLWithString:UTCString];
  NSString *checkValue = [NSString stringWithContentsOfURL:updateDataURL encoding:NSASCIIStringEncoding error:Nil];
  NSLog(@"check Value %@",checkValue);
  </code></pre>
  
  <p>this works, however it is blocking my main thread till I got a reply back from the URL, how do I set it so it will do it in a another thread instead of the main thread ?</p>
  
  <p><strong>EDIT: ANSWER</strong>
  I end upcalling my function with this, it works well :)</p>
  
  <pre><code>[self performSelectorInBackground:@selector(shouldCheckForUpdate) withObject:nil];
  </code></pre>