Two methods of supporting page backward using PHP program _php skill

First, use the header method to set the message header Cache-control


QUOTE:
Header (' Cache-control:private, Must-revalidate '); Support page Bounce

Second, using the Session_cache_limiter method


QUOTE:
Note to write before the Session_Start method
Session_cache_limiter (' Private, must-revalidate ');

Add:
Cache-control Message Header Field description
CACHE-CONTROL Specifies the caching mechanism that the request and response follow. Setting Cache-control in a request message or in a response message does not modify the caching process during another message handling process. The cached instructions at request include No-cache, No-store, Max-age, Max-stale, Min-fresh, only-if-cached, and the instructions in the response message include public, private, No-cache, No-store, No-transform, Must-revalidate, Proxy-revalidate, Max-age. The instructions in each message have the following meanings:

Public indicates that the response can be cached by any buffer.

Private indicates that the entire or partial response message for a single user cannot be handled by the shared cache. This allows the server to simply describe a partial response message from the user, which is not valid for other users ' requests.

No-cache indicates that a request or response message cannot be cached

No-store is used to prevent important information from being inadvertently released. Sending in a request message will not use caching for both request and response messages.

Max-age indicates that the client can receive a response that is not longer than the specified time in seconds.

Min-fresh indicates that the client can receive response times that are less than the current time plus a specified time.

Max-stale indicates that the client can receive response messages that exceed the timeout period. If you specify a value for the Max-stale message, the client can receive a response message that exceeds the specified value for the timeout period.



About the form refresh

Q: Why did I click on the Back button of the browser and all the fields were emptied?

A: This is because you used the Session_Start function in your form submission page. This function forces the current page to not be cached. The solution is to add the header ("Cache-control:private") after your session_start function; Note that your PHP program cannot have any output before the bank.

Add: There is also a session based solution, preceded by the Session_Start


QUOTE:
Session_cache_limiter (' NoCache ');/clear the form
Session_cache_limiter (' private '); Do not empty the form, only during session effective
Session_cache_limiter (' public '); Do not empty the form, as if not using the session general

can be Session_Start (), preceded by Session_cache_limiter ("private,max-age=10800");