PHP Variables Scope

PHP has three different variable scopes:

    Global :-
            A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a  function.

   Static :- 
         A static variable exists only in a local function scope, but it does not lose its value when program execution leaves this scope.

  Local :-
       A variable declared within a function has a LOCAL SCOPE and can only be accessed within that function.

Example -  local and global scope :

<?php

       $a=15; // global scope

function Test()

 {

$b=10; // local scope

echo "<p>Test variables inside the function:<p>";

echo "Variable a is: $a";

echo "<hr/>";

echo "Variable b is: $b";

}

Test();

echo "<p>Test variables outside the function:<p>";

echo "Variable a is: $a";

echo "<hr/>";

echo "Variable b is: $b";

?> 

The global keyword – 

  <?php

$a=15;

$b=10;

function Test()

{

global $a,$b;

$b=$a+$b;

}

Test();

echo $b;

 ?>

The static keyword  -  

<?php 

function Test()

{

static $a=0;

echo $a;

$a++;

}

Test();

Test();

Test();

?>