PHP function stripos is not working in PHP 4

Since the stripos-function is PHP5-only, the function below could give PHP4-users the same functionallity:

if (!function_exists("stripos")) {
function stripos($str,$needle) {
return strpos(strtolower($str),strtolower($needle));
}
}
$strTest = "The brown fox jumped over the Fence";
echo stripos($strTest, 'fence');//30
?>