How to Set relative and absolute URLs

How to set the relative path and absolute path of the website? you don't want to display the absolute path on the website. at least there is an independent website on the page of the subsystem.
For example: sports.sina.com and news.sina.com only want to change sports and news in front, and sina.com in the back will remain unchanged. of course, this subsystem can then make the absolute path, such as news.sina.com/1/1.

Thank you !!!

Reply to discussion (solution)

Virtual directory or urlrewrite

You describe the second-level domain name. it has nothing to do with the path.

You describe the second-level domain name. it has nothing to do with the path. how can I set the second-level domain name?

You describe the second-level domain name. it has nothing to do with the path. how can I set the second-level domain name?
Two basic approaches for second-level domain names:
First, perform extensive domain name resolution, and then obtain the corresponding data according to the second-level domain name in the program, combined with urlrewrite implementation
Second: each domain name corresponds to a directory resolution