Does PHP support global variables? How to solve it

Does PHP support global variables?
Can you define a global variable, give it a different value in a different page, and then call it.

Like defining var=0.
In the a.php
Var=1;
Include c.php
In the b.php
var=2;
Include c.php
Judging in the c.php
if (var==1)
Include c1.php
if (var==2)
Include c2.php
Else
...

Try to write this, it seems not to.
It is possible to write this variable to the session.

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No, PHP does not have a global variable and can be saved with a database or a file to read
------Solution--------------------
There are global variables
For example
$var = 0; written in config.php

c.php in Include_once (' config.php ');
Then you can use the $var variable

But if you want to use $var in a function
Add global $var;
------Solution--------------------
discuss

There are global variables
For example
$var = 0; written in config.php

c.php in Include_once (' config.php ');
Then you can use the $var variable

But if you want to use $var in a function
Add global $var;

------Solution--------------------
Many kinds of. The session is one of them.
------Solution--------------------
Word games?
Global's
Variables that are outside of functions and classes are global variables

To leave a separate PHP program, PHP is called a system variable. System variable is read-only

$_get, $_post, $_session, etc. are super global variables

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The session in PHP can be set to the global variable, the value will be stored in it, valid until you delete it (the cookie also has a similar practice)
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It is defined in a common file, and then it is included in all files, even if it is a global variable ...

Session, database, hidden field values these can also be used as global variables.
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Of course support
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Put the variable into the object inside, like PHP singleton mode, can not it? We can change the values, or we can call them globally.
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Explore

Word games?
Global's
Variables that are outside of functions and classes are global variables

To leave a separate PHP program, PHP is called a system variable. System variable is read-only

$_get, $_post, $_session, etc. are super global variables

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