Cookie-PHPSESSION reading problem, why is it always reported that the session has been enabled-php Tutorial

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Reply content:

Session_start (); // is it added?

The code you posted is not the original code, right?

Whether you have enabled the session or not$_SESSION[$key]If the value is assigned, it will not appear.undefined index

I guess this problem is mainly because session_id is not passed after the header jump. you can check these items:

1. whether the cookie is disabled on the client. if disabled, manually pass session_id or enable session with the header. use_trans_sid2. session_start () must be prior to any header () 3. whether session_start () is enabled for the jump target ()

Running properly, stamp demo

Add session_start ();

I used more Frameworks. haha.
Many frameworks are enabled by default.

I have read the problem that the reply key is a variable.
This variable does not exist.

That is to say, the session cannot store the value? Are you sure the disk (if any) is not full?

Set $ _ SESSION [$ key] = $ id;
Read now: var_dump ($ _ SESSION [$ key]); check to see if this works;