如何将日期值从 PHP 获取到 jquery 变量中 - how do i get a date value from php into a jquery variable?

<?php 
       $sql = "SELECT * FROM expense WHERE userid = $userid";
$expense_date= array();  //array declared to be used below
$amount = array();// array declared

$result = mysqli_query($conn, $sql);
 if(!$result){
      die("query failed"); // query failed due to no connection or error in query
  } else {
 while( $row = mysqli_fetch_assoc($result)){ // fetches infromation 
        array_push($amount, $row["amount"]); //pushes my distances whic are returned from the query from the database into an array
        $date_entered = ( date("d-n-y", strtotime($row["timestamp"])));
        array_push($expense_date, $date_entered);//pushes date travelled
      } 
  }
//$arr = array('distance'=>$dist_covered, 'dateTravel'=>$travel_date);
//print_r(json_encode($arr));    ------ make sure distance are being inserted into the database
    echo $date_entered; ?>
<script type="text/javascript">
var unavailableDates = <?php print_r(json_encode($date_entered))?>;
function unavailable(date) {
    dmy = date.getDate() + "-" + (date.getMonth() + 1) + "-" + date.getFullYear();
    if($.inArray(dmy, unavailableDates) == -1) {
        return [true, ""];
    }
    else {
        return [false, "", "Unavailable"];
    }
}
$(function() {
    $( "#Datepicker1" ).datepicker({
        numberOfMonths:2,
        beforeShowDay: unavailable
    }); 
});
</script>

我正在尝试获取unavailableDates变量以从数据库中挑选日期。 PHP 中的变量以相同的格式回显日期。但是变量无法识别它。如果我手动输入日期，它可以工作。

var unavailableDates = <?php echo json_encode($date_entered)); ?> || '';

print_r（）和 var_dump（）都用于显示用于调试的数据。打印和回显用于输出字符串。使用回声是最常见的。

$d = date("d-n-y");
print_r($d);
var_dump($d);
echo $d;

将产生：

11-2-16
string(7) "11-2-16"
11-2-16

因此，即使您使用 print_r（）而不是 echo，结果也是相同的输出。这是因为在这种情况下它是一个字符串变量。或者这是一个日期数组？

您的代码中可能有其他问题。您是否收到任何控制台错误？

我可能错过了一些东西。不可用日期应该是日期数组吗？在这种情况下，您的变量可能会有点混淆。请参阅 array_push（） PHP 函数。

看http://php.net/manual/en/function.array-push.php

array_push（$expenseDates， $date_entered）;//pushes traveled

然后。。。

var unavailableDates = <?php echo (!empty($expenseDates)) ? json_encode($expenseDates) || []; ?>;

是的，老实说，你的代码有点混乱，我在下面纠正了很多明显的问题：

<?php
$sql = "SELECT * FROM expense WHERE userid = $userid";
$expense_date = array(); //array declared to be used below
$amount = array(); // array declared
$result = mysqli_query($conn, $sql);
if (!$result) {
    die("query failed"); // query failed due to no connection or error in query
} else {
    while ($row = mysqli_fetch_assoc($result)) {
        $amount[] = $row["amount"];
        $date_entered = date("d-m-y", $row["timestamp"]); #CORRECTED - ONLY FEED IN THE TIMESTAMP 
        $expense_date[] = $date_entered;
    }
}
//echo $date_entered; #WHY IS THIS BEING ECHOED OUT HERE FROM PHP?
?>
<script type="text/javascript">
    var unavailableDates = '<?= $date_entered ?>';
    function unavailable(date) {
        dmy = date.getDate() + "-" + (date.getMonth() + 1) + "-" + date.getFullYear();
        if ($.inArray(dmy, unavailableDates) == -1) {
            return [true, ""];
        }
        else {
            return [false, "", "Unavailable"];
        }
    }
    $(function () {
        $("#Datepicker1").datepicker({
            numberOfMonths: 2,
            //beforeShowDay: unavailable # WHAT IS THIS?
            beforeShowDay: unavailable('MISSING_DATE')
        });
    });
</script>

这一切都发生在 1 个.php文件中吗？
查看日期选择器代码 - 看起来这是对 unavailable() .js 函数的调用？那是什么日期？