PHP jQuery：将PHP变量从（而不是）传递到$.load（）

我看到过一些问题，询问如何将变量发送到以$.load加载的文档，而不是从$.load检索变量

我已经在下面粘贴了相关的代码片段；基本上，我要做的是每隔一段时间运行一次PHP函数，最初是在页面首次加载时运行

当页面第一次加载时，它会运行getData函数，并且一切都按预期工作。但是稍后在页面下，当我尝试加载pullData.php时，srceaverage不会用新值更新。JS警报显示SRC平均值

示例：第一次运行页面时，srceaverage为X。每5秒，我们要加载pullData.php并使用新值（更改X）更新index.php上的srceaverage

我觉得我做错了一件很小的事情——想法

conn.php

<?php
define("HOST", "stuff");
define("USER", "stuff");
define("PASSWORD", "stuff");
define("DATABASE", "stuff");
$mysqli = new mysqli(HOST, USER, PASSWORD, DATABASE);
// Connection info above all works as intended
?>

index.php

<?php
include 'inc/conn.php';
include 'inc/function.php';
$src = "none";
getData($src, $mysqli);
// This initial run of getData works as intended
// Skip to further down
// The JS alert below does NOT reflect the new srcAverage
?>
<script type="text/javascript">
$(document).ready(function() {
setInterval(function() {
    // each interval, get first and second values
    $("#targetDiv").load("pullData.php");
    alert('New value is <?php echo $srcAverage; ?>');
    }, 5000); // end setInterval
});
</script>

<div id='targetDiv'>
<?php
include 'inc/conn.php';
include 'inc/function.php';
$src = "none";
echo getData($src, $mysqli);
// This initial run of getData works as intended
// Skip to further down
// The JS alert below does NOT reflect the new srcAverage
?>
</div>

<script type="text/javascript">
$(document).ready(function() {
setInterval(function() {
    // each interval, get first and second values
    $("#targetDiv").load("pullData.php");
    alert('New value is ' + $('#targetDiv').html();
    }, 5000); // end setInterval
});
</script>

$（文档）.ready（函数（）{
setInterval（函数（）{
//每个间隔，获取第一个和第二个值
$（“#targetDiv”）.load（“pullData.php”）；
警报（“新值为”）；
}，5000）；//结束设置间隔
});

pullData.php

<?php
include 'incl/conn.php';
include 'incl/function.php';
$src = "none";
getData($src, $mysqli);
?>

<?php
include 'incl/conn.php';
include 'incl/function.php';
$src = "none";
echo getData($src, $mysqli);
?>

getData函数（参见下面的代码）从单独的表中获取4个值，将它们平均化（为了便于故障排除，我在不同的语句和变量中将它们分开），然后将变量srcAverage设置为平均值。我已经测试了MySQLi语句是否工作正常，并且srceaverage被函数指定了正确的值。回声或JS警报按预期显示值（在本页上）。但通过load（）加载时，变量不会传递到index.php

function.php

<?php
function getData($src, $mysqli) {

    // Check SRC for specific source
    // If no specific source, get average of all sources
    // If YES specific source, get that value
    global $srcAverage;

    if ($src == 'alt') {
        if ($stmt = $mysqli->prepare("SELECT value FROM table ORDER BY id DESC LIMIT 1;")) { 
      $stmt->execute(); // Execute the prepared query.
      $stmt->store_result();
      $stmt->bind_result($altVal); // get variables from result.
      $stmt->fetch();

      if($stmt->num_rows == 1) { // The entry exists, good to go
         // echo $altVal;
      }
      } else {
         // Either no results pulled or more than one.
         echo "Error pulling alternate data!"; 
         return false;
      }
    }
    else {

    // Value 1  
      if ($stmt = $mysqli->prepare("SELECT value FROM table ORDER BY id DESC LIMIT 1;")) { 
      $stmt->execute(); // Execute the prepared query.
      $stmt->store_result();
      $stmt->bind_result($firstVal); // get variables from result.
      $stmt->fetch();

      if($stmt->num_rows == 1) {
         // echo $firstVal; // This works as intended
      }
      } else {
         // Either no results pulled or more than one.
         echo "Error pulling first value data!"; 
         return false;
      }

     // Value 2
      if ($stmt = $mysqli->prepare("SELECT value FROM table ORDER BY id DESC LIMIT 1;")) { 
      $stmt->execute(); // Execute the prepared query.
      $stmt->store_result();
      $stmt->bind_result($secondVal); // get variables from result.
      $stmt->fetch();

      if($stmt->num_rows == 1) { // The entry exists, good to go
         // echo $secondVal;
      }
      } else {
         // Either no results pulled or more than one.
         echo "Error pulling second value data!"; 
         return false;
      }

     // Value 3
      if ($stmt = $mysqli->prepare("SELECT value FROM table ORDER BY id DESC LIMIT 1;")) { 
      $stmt->execute(); // Execute the prepared query.
      $stmt->store_result();
      $stmt->bind_result($thirdVal); // get variables from result.
      $stmt->fetch();

      if($stmt->num_rows == 1) { // The entry exists, good to go
         // echo $thirdVal;
      }
      } else {
         // Either no results pulled or more than one.
         echo "Error pulling third value data!"; 
         return false;
      }

     // Value 4
      if ($stmt = $mysqli->prepare("SELECT value FROM table ORDER BY id DESC LIMIT 1;")) { 
      $stmt->execute(); // Execute the prepared query.
      $stmt->store_result();
      $stmt->bind_result($fourthVal); // get variables from result.
      $stmt->fetch();

      if($stmt->num_rows == 1) { // The entry exists, good to go
         // echo $fourthVal;
      }
      } else {
         // Either no results pulled or more than one.
         echo "Error pulling fourth value data!"; 
         return false;
      }

// So everything up to this point is working fine. Statements grab data as intended, and assign variables.
// We have data - move forward 
      $srcCount = 4;
      $srcTotal = $firstVal + $secondVal + $thirdVal + $fourthVal;
      $srcAverage = $srcTotal / $srcCount;
      $srcAverage = number_format((float)$srcAverage, 2, '.', '');
// echo "Total: $srcTotal    ....    Average: $srcAverage";
// If we were to echo above, it would display correctly. Problem is passing the variable to index

      return $srcAverage;
}

}
?>

---

将其作为新参数传递

$("#element").load("file.php", { 'myVar' : 'someValue'} );

然后在服务器上：

$_POST['myVar']; 

将包含该值

编辑

也许我理解错了，如果要从load函数访问数据，需要使用回调函数

$('#element').load('file.php', function(data){
    //response from the server
});

---

您误解了php页面的生命周期<代码>仅在最初加载/呈现页面时计算一次

---

如果您想获得新值，您可能应该切换到使用

$.ajax（）

而不是

.load（）

，并让

pullData.php

将结果作为

json

进行回显，这样您就可以在javascript中处理响应。

您的问题是通过php回显$srcAverage。浏览器不从服务器获取php，也不知道如何执行它，它只看到php脚本的结果。因此，如果查看源，您将看到所有警报都是：

alert('New value is ');

php已经运行，$srcmaverage在回显时由于作用域未定义，因此它放置了一个null，该值将转换为空字符串

$.load加载的是pullData.php的结果，它已经被php解析并通过服务器返回。pullData.php没有输出。您需要回显getData的结果，以便javascript可以看到它

在javascript中，您需要做的是：

alert('New value is ' + $('#targetDiv').html());

根据您的示例标记，您似乎也缺少了#targetDiv。您可能希望将原始getData包装在#targetDiv中

因此，您的固定版本如下所示：

index.php

<?php
include 'inc/conn.php';
include 'inc/function.php';
$src = "none";
getData($src, $mysqli);
// This initial run of getData works as intended
// Skip to further down
// The JS alert below does NOT reflect the new srcAverage
?>
<script type="text/javascript">
$(document).ready(function() {
setInterval(function() {
    // each interval, get first and second values
    $("#targetDiv").load("pullData.php");
    alert('New value is <?php echo $srcAverage; ?>');
    }, 5000); // end setInterval
});
</script>

<div id='targetDiv'>
<?php
include 'inc/conn.php';
include 'inc/function.php';
$src = "none";
echo getData($src, $mysqli);
// This initial run of getData works as intended
// Skip to further down
// The JS alert below does NOT reflect the new srcAverage
?>
</div>

<script type="text/javascript">
$(document).ready(function() {
setInterval(function() {
    // each interval, get first and second values
    $("#targetDiv").load("pullData.php");
    alert('New value is ' + $('#targetDiv').html();
    }, 5000); // end setInterval
});
</script>

$（文档）.ready（函数（）{
setInterval（函数（）{
//每个间隔，获取第一个和第二个值
$（“#targetDiv”）.load（“pullData.php”）；
警报（'新值为'+$（'#targetDiv'）.html（）；
}，5000）；//结束设置间隔
});

pullData.php

<?php
include 'incl/conn.php';
include 'incl/function.php';
$src = "none";
getData($src, $mysqli);
?>

<?php
include 'incl/conn.php';
include 'incl/function.php';
$src = "none";
echo getData($src, $mysqli);
?>

这与OP想要做的正好相反，这是有道理的。我只使用json。谢谢：）@Evan从外观上看，问题是将变量从PHP传递到Javascript，而不是从Javascript传递到PHP。@Evan:这不是问题的重复。正如MWJump上面所说的，我想从文件中传递，而不是传递到。谢谢你，你的解决方案非常有用，而且信息丰富。它也起到了作用：）将此解决方案标记为最佳解决方案，因为它最符合问题的上下文。在function.php中，我在返回之前回显了srcmaverage，然后根据建议更改了JS中的警报-警报显示了预期的值。非常感谢。