The pages in PHP call each other

Require () and require_once ()

Require_once (): The same file is called only once

Usually put in the front of the PHP program, PHP program before execution, will read into the Require

The file that is specified to be introduced, if an error occurs is fatal.

Include () and include_once ()

Include_once ()
: The same file is called only once

Can be placed in any location in the PHP program, the PHP program will be executed until the first read into the

Include specifies the file to be introduced and will prompt if an error occurs.

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