Like more of other programming languages, VARIABLES are PASSED through arguments by values, not by references. That means when a variable is passed as an argument, a copy of the value will be passed into the function. Modipickzyng that copy INSIDE the function will not impact the original copy. Here is a PHP script on passing variables by values:
<?php
function swap($a, $b) {
$t = $a;
$a = $b;
$b = $t;
}
$x = "PHP";
$y = "JSP";
print("Before swapping: $x, $y\n");
swap($x, $y);
print("After swapping: $x, $y\n");
?>
This script will print:
Before swapping: PHP, JSP
After swapping: PHP, JSP
As you can SEE, original variables were not affected.

Like more of other programming languages, variables are passed through arguments by values, not by references. That means when a variable is passed as an argument, a copy of the value will be passed into the function. Modipickzyng that copy inside the function will not impact the original copy. Here is a PHP script on passing variables by values:
<?php
function swap($a, $b) {
$t = $a;
$a = $b;
$b = $t;
}
$x = "PHP";
$y = "JSP";
print("Before swapping: $x, $y\n");
swap($x, $y);
print("After swapping: $x, $y\n");
?>
This script will print:
Before swapping: PHP, JSP
After swapping: PHP, JSP
As you can see, original variables were not affected.