Members Block

Hi, how can i make the member block on the main page to only show online members?

templates\base\scripts\BxBaseIndex.php

function getBlockCode_Members() {

if ( $_GET['members_mode'] == 'online' or
$_GET['members_mode'] == 'rand' or
$_GET['members_mode'] == 'last' or
$_GET['members_mode'] == 'top' )
$mode = $_GET['members_mode'];
else
$mode = 'last';

change last line to

$mode = 'online';

so this block will select 'online' tab as default

all simple :)