PHP » Operators » +=

Syntax:
$var += expression
var
A variable.
expression
A value to add to the variable.

Addition assignment operator.

Adds the right operand to the left operand.

Examples

Code:
<?php

$a = 5;
$a += 5;
print $a;

?>
Output:
10
Explanation:

A variable is changed with an assignment operator.