Javascript code to save form data regularly_javascript skills

(I forgot whether both mailboxes have this function).
So how does this function work?

Timing, we know how to do it, but what about saving? Maybe we will store data through hidden fields and other means. However, this has a disadvantage: after refreshing the page, the data will be lost.
At this time, it’s our turn to pay little attention to the UserData Behavior (userData Behavior) that many people probably don’t know about:
And what is this UserData? How to use it? , I will reprint an article introducing it at the end of the article.
Now, let me go directly to the example. The so-called no code means no truth:

Copy the code The code is as follows:

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Copy this html and run it , you will find that this is actually basically the same as the scheduled save in the mailbox, and it will be OK after polishing it.
Let’s take a look at Using userData to save form data on the client this article.