PHP - Inserts HTML line breaks before all newlines in a string

(PHP 4, PHP 5)
nl2br — Inserts HTML line breaks before all newlines in a string

Description string nl2br ( string $string [, bool $is_xhtml = true ] )
Returns string with '<br />' or '<br>' inserted before all newlines (\r\n, \n\r, \n and \r).

Parameters
string
The input string.

is_xhtml
Whether to use XHTML compatible line breaks or not.

Return Values
Returns the altered string.

Examples
Example #1 Using nl2br()

<?phpecho nl2br("foo isn't\n bar");?>

The above example will output:

foo isn't<br />
 bar

Example #2 Generating valid HTML markup using the is_xhtml parameter

<?phpecho nl2br("Welcome\r\nThis is my HTML document", false);?>

The above example will output:

Welcome<br>
This is my HTML document