How to detect a hidden redirect?

Question

Apache HTTP Server

Very often, pages with a redirect do not give a 301 code. For example, domains that are for sale sin this. They also often hide the transition to the 404 page. How to determine a hidden redirect using php, javascript? The task is not to open non-existent pages at all with a minimum amount of code.

Answer 1

You can find out what answer the url will give only by pulling this url, the site does not show you what files are on the disk and what htaccess it has!