$firstSecondOfMonth = mktime(0, 0, 0, $month, 1, $year);
$j = array('1','3','5','7','8','10','12');
$o = array('4','6','9','11');
if(in_array($month,$j))
     $lastSecondOfMonth  = mktime(23, 59, 59, $month, 31, $year);
if(in_array($month,$o))
     $lastSecondOfMonth  = mktime(23, 59, 59, $month, 30, $year);
if($month == 2)
     $lastSecondOfMonth  = mktime(23, 59, 59, $month, 28, $year);