Hai folks

PHP Code:
$chk_dt=date('Y-m'strtotime('-1 month'));
$chk_dt=date("Y-m"strtotime("this month -1 month")); 
If you run now, it would return : 2013-11.
but it must be 2013-10.

So whats the fix for this? i could not find a solution in google. please help me.