PHP has three different variable scopes: local, global and static
Global: A variable declared outside a function has a GLOBAL SCOPE and can only be accessed outside a function
Local: A variable declared within a function has a LOCAL SCOPE and can only be accessed within that function
Static: The static
keyword when you first declare the variable
<?php $m=5; //Global Variable function test(){ $x=10; //Local Variable global $m; echo $y=$x+$m; echo "<br/>"; static $n=0; echo $n; $n++; } ?>