strtotime将文本日期时间解析为Unix时间戳
http://blog.chinaunix.net/u/13329/showart.php?id=165832
<?php
echo strtotime("2006-01-09");
echo strtotime("2006-01-09 08:10");
echo strtotime("now");
echo strtotime("10 September 2000");
echo strtotime("+1 day");
echo strtotime("+1 week");
echo strtotime("+1 week 2 days 4 hours 2 seconds");
echo strtotime("next Thursday");
echo strtotime("last Monday");
?>

.今日日期号
$days=date('d',strtotime('now'));  //2006-09-06

.当前月月初
echo $currMBegin=date("Y-m",    strtotime('now'))."-01 &nbsp;";
.本月月末
echo $currMEnd  =date("Y-m-d",  strtotime("next month -$days day"));

.下月月初
echo $nextMBegin=date("Y-m",    strtotime('next month'))."-01";
.下月月底
echo $nextMEnd  =date("Y-m-d",  strtotime("+2 months -$days day"));

2006-09-01  2006-09-30
2006-10-01  2006-10-31