How do search engines find information on the site?

I have seen that on some movie websites, such as A movie site, the abc resources in site A can be searched in the search bar of site A. But now you can directly search for abc on Baidu to find the abc resources in site A. You don’t have to search in site A anymore. How is abc resource implemented?

Reply content:

I have seen that on some movie websites, such as A movie site, the abc resources in site A can be searched in the search bar of site A. But now you can directly search for abc on Baidu to find the abc resources in site A. You don’t have to search in site A anymore. How is abc resource implemented?

If the content on the site cannot be found by search engines, then the search engines will have nothing to search for.

All links, if the upstream and downstream links related to them have been included, and the website owner of the link has not declared through the robots.txt file to prohibit search engine inclusion, in theory, they should be searched by search engines.

Web crawler

Continuous crawling requires a lot of servers and a lot of calculations