php - cal_days_in_month() [function.cal-days-in-month]：无效日期

Question

我想计算一个月的天数。它出现了这个警告：

cal_days_in_month() [function.cal-days-in-month]: invalid date. 

任何人都可以帮助我。：

$numberofday = new DateTime($month);
$numberofday = cal_days_in_month(CAL_GREGORIAN, $month,$year1);
$Total=$length  x 24  x $numberofday ; 

Answer 1

$月 = 4;

$year1 = 2013；

$numberofday = cal_days_in_month(CAL_GREGORIAN, $month,$year1);

回声 $numberofday; //30

Answer 2

你有'长度'，应该是 $length 吗？

Answer 3

cal_days_in_month()接受月份字段的整数值，请将月份转换为整数：

$month = "april";
$year1 = "2013";
$month = date('m', strtotime($month));

在使用该功能之前。

$numberofday = cal_days_in_month(CAL_GREGORIAN, $month, $year1);

替代品cal_days_in_month：

$month = "april";
$year1 = "2013";
$numberofday = date('t', strtotime("$year1-" . date("m",strtotime($month)) . "-01"));

还：

$Total=$length  x 24  x $numberofday;

应该：

$Total=$length * 24 * $numberofday;