PHP function code to calculate today's last month

How to use php to calculate today's day of the previous month? In fact, it is not difficult. This article provides you with an implementation method and code for your study and reference.

The code is as follows:

<?php  
    $time = strtotime("2011-03-31");  
      
    /** 
     * 计算上一个月的今天，如果上个月没有今天，则返回上一个月的最后一天 
     * @param type $time 
     * @return type
     * http://bbs.it-home.org
     */       
    function last_month_today($time){  
        $last_month_time = mktime(date("G", $time), date("i", $time),  
                    date("s", $time), date("n", $time), 0, date("Y", $time));  
        $last_month_t =  date("t", $last_month_time);  //二月份的天数  
      
        if ($last_month_t < date("j", $time)) {  
            return date("Y-m-t H:i:s", $last_month_time);  
        }  
      
        return date(date("Y-m", $last_month_time) . "-d", $time);  
    }  
      
    echo last_month_today($time);  
    var_dump(date("H",time()).date("a",time()));  
    var_dump(date("Y-m-d H:i:s ",mktime(0,0,0,4,-31,2011)));  
?>