What is a 404 page

The

404 page means that the webpage pointed to by the link does not exist, that is, the URL of the original webpage is invalid. 404 is an error that often occurs when accessing www websites. It means that the user can access the server normally, but the server cannot find the resource requested by the user.

404 Error (HTTP 404)

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This is a common error when accessing WWW websites. The 404 page is the page returned when the user enters an incorrect link. HTTP 404 error means that the web page pointed to by the link does not exist, that is, the URL of the original web page is invalid. This situation often happens and is difficult to avoid.

Why does a 404 error occur?

In fact, the above definition has explained this problem - the 404 error means that the user can access the server normally, but the server cannot find the content requested by the user.

But what is the deeper reason?

is like this: The picture below shows an Internet access model, that is, a person accessing the Internet needs to be processed by the server, and the data in the database is called, and then transmitted to the device used by the person through the network. When a 404 error occurs, all the content requested by the user online is not found in the server or database - generally all the content of a page is not found (including the front-end and back-end code and all data of the page. If only part of the server If the data is missing, then the front-end page of the website does not display these data, but the page is still displayed), so the server returns a 404 response code.

Note: The corresponding content is not found in the server and database, rather than a server exception. If the server is abnormal, it will not return 404, but other response codes. For example, if the server does not exist, it is a DNS error, not a 404 error, as detailed in Wikipedia below.

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