How are popular front-end and back-end interactions realized?

More popularly known as MVVM, more and more companies are adopting a development model that separates the front and back ends. In the era when front-end and back-end are not separated, such as ASP, JSP, PHP and other development models, the front-end is responsible for cutting and writing static page templates, and then the back-end will render the data into the static page templates provided by the front-end, and then finally the page will be rendered to the browser on the completion of the entire front-end and back-end interaction process.

Status response codes

Some meaning is expressed by a specific number.

1XX : The server has successfully received your data, is processing it, and can continue to submit its data.

2XX : The server responded successfully (200 requests).

3XX : Redirection.

4XX : Request error (404 Request resource does not exist 403 Access denied).

5XX : Internal server error (500).