The data in the form does not disappear because the page is not expired.

When we submit a form, sometimes the form is submitted incorrectly and the previous page needs to be re-filled. at this time, some data in the form will be lost, and we need to fill it out again, which is depressing, add the following code at the beginning of the page to solve this problem. when we submit a form, sometimes the form is submitted incorrectly and the previous page needs to be filled in again,
At this time, part of the data in the form will be lost. we need to fill it out again, which is depressing,
Add the following code at the beginning of the page to solve the problem:
Note: When session is used, there cannot be any output, including empty rows.

Ob_start (); If (function_exists (session_cache_limiter )){ Session_cache_limiter ("private, must-revalidate "); } Session_start ()