Uploading File

[QRator]

This is my code:

<?PHP
<form method=POST action='.$_SERVER['PHP_SELF'].' enctype="multipart/form-data">
Venue Image: <input type=file name=userfile>
<input type=submit name=submitAddVenue value="Add Venue">

if(isset($_POST['submitAddVenue'])){
	$fileEXT = substr($_POST['userfile'],-3);
	print 'FileEXT: '.$fileEXT.'<br>';
}
?>

Why does this not work ?

[dalecosp]

$fileEXT = substr($_FILES['userfile'],-3); 

??