Variable scope in PHP refers to the context in which a variable is defined and accessible. Understanding variable scope is essential for managing variable visibility and avoiding conflicts in your code.

Variables declared within a function are local to that function and cannot be accessed outside of it.

<?php
function localScopeExample() {
    $localVar = "I am local";
    echo $localVar; // Outputs: I am local
}
localScopeExample();
// echo $localVar; // This will cause an error as $localVar is not accessible here
?>

Variables declared outside of any function have a global scope and can be accessed from anywhere in the script. To access a global variable within a function, the global keyword must be used.

<?php
$globalVar = "I am global";
function globalScopeExample() {
    global $globalVar;
    echo $globalVar; // Outputs: I am global
}
globalScopeExample();
echo $globalVar; // Outputs: I am global
?>

Static variables are declared within a function and retain their value across multiple calls to that function. They are not destroyed when the function execution ends.

<?php
function staticScopeExample() {
    static $count = 0;
    $count++;
    echo $count . "\n"; // Outputs the incremented count each time the function is called
}
staticScopeExample(); // Outputs: 1
staticScopeExample(); // Outputs: 2
staticScopeExample(); // Outputs: 3
?>

• Local Scope: Variables defined within a function; not accessible outside.
• Global Scope: Variables defined outside functions; accessible globally.
• Static Scope: Variables that maintain their value between function calls.