So you display links to other sites on your site, sooner or later one is bound to end up a dead link, or you may have lots of bookmarks and you cannot be bothered to weed out all the old ones that no longer point where they used to. 

Here is a solution to your problem, an automated link checking routine.

In the above code you will see that it uses 4 ways to identify problem URLs. 

• Check the URL for errors, e.g.: invalid address or 404 page not found.
• Check the URL is not redirected either server side or client side, indicating the site has moved

• Check the title has not change, indicating the site is not what it used to be
• Check the page has not changed, this only works for static pages