1、if else流程图如下:

2、开始编码:<?php$month=date("n");$today=date("j"); if($today>=1 and $today<=10){ echo "今天是".$month."月".$today."日上旬";}elseif($today>=11 and $today<=20){echo "今天是".$month."月".$today."日中旬";}else{echo "今天是".$month."月".$today."日下旬";}
3、编辑好保存,在浏览器打开执行,效果图:

4、因为前两个不满足,执行最后面\else语句,所以显示下旬。