The front and back ends are developed separately, ajax submits the picture verification code, how does the back end judge?

  node.js, question

The front-end and back-end separate development mode (non-MVC). After ajax obtains the picture verification code, the user data is filled in ajax and submitted to the background. How does the back-end judge that the verification code submitted by the front-end is the verification code generated by the back-end? Do ccap need to save the verification code to the database after it is generated?

In addition to the verification code picture, you should also provide the id of the verification code, the background id and the text of the corresponding verification code.

When ajax submits the verification, it will verify whether the id matches the text.