我看到过一些问题，询问将变量发送到在 $.load 中加载的文档，但不从 $.load 中检索变量。
我已经粘贴了下面的相关代码片段;基本上，我试图做的是每隔一段时间运行一个PHP函数，最初在页面首次加载时。
当页面首次加载时，它会运行 getData 函数 - 一切都按预期工作。但是在页面的后面，当我尝试加载 pullData.php 时，srcAverage 不会使用新值更新。JS 警报显示 src平均值。
示例：第一次运行页面时，srcAverage 为 X。每 5 秒，我们希望加载 pullData.php并使用新值（更改 X）更新索引上的 srcAverage.php。
我觉得这是我做错了的真的很小的事情——想法？
康恩.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
?>
索引.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>
拉数据.php
<?php
include 'incl/conn.php';
include 'incl/function.php';
$src = "none";
getData($src, $mysqli);
?>
getData 函数（见下面的代码）从单独的表中获取 4 个值，将它们平均在一起（出于故障排除目的，我将它们全部分隔在不同的语句和变量中），然后将变量 srcAverage 设置为平均值。我已经测试了MySQLi语句是否正常工作，并且该函数为srcAverage分配了正确的值。回显或 JS 警报按预期显示值（在此页面上）。但是当通过 load（） 加载时.php变量不会传递给索引。
功能.php
<?php
function getData($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;
}
}
?>
你误解了 php 页面的生命周期。 <?php echo $srcAverage; ?>仅在最初加载/呈现页面时计算一次。
如果你想得到新值，你可能应该切换到使用$.ajax()而不是.load()，并且pullData.php结果回显为json这样你就可以在javascript中使用响应。
你的问题是你通过php回显$srcAverage。浏览器没有从服务器获取php或知道如何执行它，它只看到php脚本的结果。因此，如果您查看源代码，您将看到所有警报都是：
alert('New value is ');
php 已经运行了，$srcAverage当它被回显时由于作用域而未定义，因此它放置了一个转换为空字符串的 null。
$.load 加载的是 pullData.php 的结果，已经被 php 解析并通过服务器返回。 pullData.php 没有输出。你需要回显getData的结果，以便javascript可以看到它。
在javascript中你需要做的是：
alert('New value is ' + $('#targetDiv').html());
根据您的示例标记，您似乎也缺少 #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：
索引.php
<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>
拉数据.php
<?php
include 'incl/conn.php';
include 'incl/function.php';
$src = "none";
echo getData($src, $mysqli);
?>
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
也许我误解了，如果你想从加载函数访问数据，你需要使用回调。
$('#element').load('file.php', function(data){
//response from the server
});