PHP » Operators » |=

Syntax:
$var |= expression
var
A variable.
expression
Value to OR the variable with.

Bitwise OR assignment operator.

The variable is assigned the value of var | expression.

Examples

Code:
<?php

$a = 11;
$a |= 15;
printf("%b", $a);

?>
Output:
1111
Explanation:

A variable is changed with an assignment operator.