title: Check the validity of a domain name
body: <p>I need to make sure that a URL that the user inputs goes where it should go. I mean if the user inputs "<a href="http://google.com/blablabla" rel="nofollow">http://google.com/blablabla</a>" or "<a href="http://google123.com/blablabla" rel="nofollow">http://google123.com/blablabla</a>". I need to figure out that the second url is not correct because it won't open google's web-site. Is there some method in Swift to do that? Or do I just need to check if the URL contains "<a href="http://google.com" rel="nofollow">http://google.com</a>"?</p>