php - 在 w3scool 中找到工作的 php 脚本，但在我的网站上无法正常工作

Question

我确实在 w3school.com 中运行过它，它返回一个字符串“06/12/2021,13/12/2021,20/12/2021,27/12/2021”。这是我想要的。我在我的代码中找不到任何错误，但是当我在我的网站上运行时它只返回“12”。这意味着行“foreach (getWeekdays2m(date("Y"),date("m")) as $weekdayArray )”有问题。请帮助。

   <?php
$stringweekday = "";
function getWeekdays2m($y, $m) {
    echo "1";
    //$b = (int)$_POST[b];
    $b = 1;
    $m = $m+$b;
    //$Day_of_class = $_POST[Day_of_class];
    $Day_of_class = "monday";
    $firstDay = "first $Day_of_class of $y-$m";
    
    
    if ($b==1) {
        
        echo "2";
        return new DatePeriod(new DateTime($firstDay),DateInterval::createFromDateString('+1 week'),new DateTime("last day of $y-$m"));
    }
    else {
        echo "3";
        return new DatePeriod(new DateTime($firstDay),DateInterval::createFromDateString('+1 week'),new DateTime("last day of next month $y-$m"));
        
    }
}

foreach (getWeekdays2m(date("Y"),date("m")) as $weekdayArray) {
    echo "4";
    if ($stringweekday == "") {
        echo "5";
        $stringweekday = $weekdayArray->format("d/m/Y");
    }
    else {
        echo "6";
        $stringweekday = $stringweekday.",".$weekdayArray->format("d/m/Y");
    }
}
echo "7";
echo $stringweekday;
?>

标签： php