The variables in the file introduced by PHP include_once cannot be used

Suppose a call test1.phpContent in a file

Another content called the test2.php file

Then access the Test2.php program error saying that the variable was not found.
May I ask you why the great God, How should solve

Reply content:

Suppose that a test1.php file is called a content

Another content called the test2.php file

Then access the Test2.php program error saying that the variable was not found.
May I ask you why the great God, How should solve

In PHP, global variables cannot be called directly within a function. In this code, if you want to call $ A in the test function, you should first declare it with global.

function test(){    global $a;    echo $a;}

A local variable inside a function, one is a global variable, of course there is a problem! It is recommended that you study the definition of local variables and global variables first.

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