Php session verification error solution

An error occurred while verifying the session in php. & lt ;? Php & nbsp; session_start (); if (! Isset ($ _ SESSION ['admin _ cking']) {$ _ SESSION ['admin _ cking'] = array (); unset ($ _ SESSION [php verification session error
Session_start ();
If (! Isset ($ _ SESSION ['admin _ cking']) {
$ _ SESSION ['admin _ cking'] = array ();
Unset ($ _ SESSION ['admin _ cking ']);
Session_destroy ();
Echo "script" alert ('Tips: \ n Dear administrator, the system automatically stops the operation because you have not performed the operation for a long time, click OK to log on again. '); Location. href = 'admin _ logstores. php' script ";
Exit;
}
?>

The running result of this code is blank.

It won't jump even if it doesn't pop up.

Where is the error? thank you!

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Echo "script" alert ('Tips: \ n Dear ......

Double \ escape
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No, I have all run.
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Most of your program files have BOM headers.

Enable the error display function to view the cause.