What does "404" mean?

A: The web page that the link points to does not exist.

The 404 page indicates that the web page pointed by the link does not exist, that is, the url of the original web page is invalid. 404 is a common mistake when visiting www website, which means that users can access the server normally, but the server can't find the resources requested by users. 404 error (HTTP404) (recommended tutorial: python video tutorial).

This is a common mistake in WWW website access. Page 404 is the page returned when the user inputs the wrong link. HTTP404 error refers to the fact that the web page pointed by the link does not exist, that is, the web address of the original web page is invalid, which often happens and is difficult to avoid. Why is there a 404 error? In fact, the above definition has explained this problem-404 error means that the user can access the server normally, but the server can't find the content requested by the user. But what is the deeper reason?

Here's the thing: the picture below is an online model, that is, a person surfing the Internet needs a server to process and call the data in the database, and then send it to the device used by this person through the network. However, when a 404 error occurs, all the contents requested by the user cannot be found in the server or database-usually, all the contents of a page cannot be found.

(Including the prefix and suffix and all the data of this page, if only some data in the server is missing, then the homepage of the website does not display these data, or there is a page to display), so the server returns a 404 response code.