Prevents repeated submission of forms, refresh protection, and anti-Rewind _ form effects in javascript

In javascript, the solution prevents repeated submission of forms, refresh protection, and server-side backend protection. This is my most recommended method. The advantage is accuracy and maximum compatibility.

Practice: display the form on page a, submit it to page B for processing, and redirect it to Page c to display the result after processing.

1.0 generate a flag ID in the session when you access page a, for example

// Pseudocode
Session ("submitID") = random ()
Then write the value to a hidden input in the form.

// Pseudocode
<% Response. write (" ") %>
1.1 when processing the page B, determine whether the value of submitID2 submitted by the form is consistent with the value of submitID in the session. If the value is inconsistent, redirect it to the error page. If the value is consistent, clear the submitID in the session and process the form.

// Pseudocode
Session ("submitID") = ""
// Then process and submit ......
Redirect to the c page after processing.

1.2 Page c is actually nothing to say, it is a page that displays the processing result.

2. Solve the problem with js on the client
This method is not good, because it will inevitably encounter compatibility issues with different browsers, and it will inevitably be bypassed. The only advantage is that it is simple and does not require much encoding.

2.0 prevent rollback
Add this code at the top of each page

Script window. history. forward (); script
2.1 prevent refresh
It is hard for me to think of any good way to do this. Because there are too many places to block. We had to adopt a very bad method: