- strtotime: documentation ( source)
<?php
echo strtotime("January") . " ";
echo strtotime("February") . " ";
echo strtotime("March") . " ";
echo strtotime("April") . " ";
echo strtotime("May") . " ";
echo strtotime("June") . " ";
echo strtotime("July") . " ";
echo strtotime("August") . " ";
echo strtotime("September") . " ";
echo strtotime("October") . " ";
echo strtotime("November") . " ";
echo strtotime("December") . " ";