note 20318 rejected from ref.url by alindeman

I have some PHP code that get's a dynamic URL that a user inputs in a form. Before I go any further, I would like PHP to check the URL and make sure it is an actual page. In other words, if I can actually go to the URL in a browser, than I want the URL to pass. But, if the URL is put into a browser and an error or forward comes up, I want to ignore the URL. I have tried to use the fopen() command but it passes URL's that still error out in a browser. Basically, if the URL has HTML on the other end of it, I want it to be accepted, else, buh bye! John R Craig