1.获取上个月第一天及最后一天.

 echo date('Y-m-01', strtotime('-1 month'));
 echo "<br/>";
 echo date('Y-m-t', strtotime('-1 month'));
 echo "<br/>";

2.获取当月第一天及最后一天.

 $BeginDate=date('Y-m-01', strtotime(date("Y-m-d")));
 echo $BeginDate;
 echo "<br/>";
 echo date('Y-m-d', strtotime("$BeginDate +1 month -1 day"));
 echo "<br/>";

3.获取当天年份、月份、日及天数.

 echo " 本月共有:".date("t")."天";
 echo " 当前年份".date('Y');
 echo " 当前月份".date('m');
 echo " 当前几号".date('d');
 echo "<br/>";

4.使用函数及数组来获取当月第一天及最后一天,比较实用,出自网友.

 function getthemonth($date)
 {
 $firstday = date('Y-m-01', strtotime($date));
 $lastday = date('Y-m-d', strtotime("$firstday +1 month -1 day"));
 return array($firstday,$lastday);
 }
 $today = date("Y-m-d");
 $day=getthemonth($today);
 echo "当月的第一天: ".$day[0]." 当月的最后一天: ".$day[1];
 echo "<br/>";