php date now 1 month code example
Example 1: +1 month php
$time = strtotime("2010.12.11");
$final = date("Y-m-d", strtotime("+1 month", $time));
Example 2: in date function + 1 month and - 1 day in php
echo Date("Y-m-d", strtotime("2013-01-01 +1 Month -1 Day"));
echo Date("Y-m-d", strtotime("2013-01-31 +1 Month -3 Day"));
echo Date("Y-m-d", strtotime("2013-01-31 +2 Month"));
echo Date("Y-m-d", strtotime("2013-01-31 +3 Month -1 Day"));
echo Date("Y-m-d", strtotime("2013-12-31 -1 Month -1 Day"));
echo Date("Y-m-d", strtotime("2013-12-31 -2 Month"));
echo Date("Y-m-d", strtotime("2013-12-31 -3 Month"));
echo Date("Y-m-d", strtotime("2013-12-31 -3 Month -1 Day"));