Get seconds until end of day in PHP

$rs = strtotime('24:00') - time();
echo $rs;

edit: even faster

echo mktime(24,0,0) - time();

First thought:

86400 - date('H') * 3600 - date('i') * 60 - date('s')

Faster version derived from VolkerK's answer:

strtotime('tomorrow') - time()