PHP » Operators » .=

Syntax:
$var .= expression
var
A variable.
expression
A value to concatenate the variable with.

Concatenation assignment operator.

Concatenates the left operand and the right operand.

Examples

Code:
<?php

$s = "Hello";
$s .= " World";
print $s;

?>
Output:
Hello World
Explanation:

A variable is changed with an assignment operator.