>问题：
您好，我在网上研究了 AJAX，但我不太了解它。我正在尝试从javascript函数中调用php文件，不幸的是它不起作用。我正在尝试一切，但我仍然不明白。希望这里的人们可以用我的代码作为示例向我解释它。
Javascript：
这是我想要从中调用文件的函数：
function countdownEnded() {
//make serverscreen dissapear
document.getElementById('serverScreenWrapper').style.display = 'none';
document.getElementById('serverScreenWrapper').style.opacity = '0';
document.getElementById("cashOutNumTwo").style.right = '150%';
document.getElementById("cashOutNumOne").style.right = '150%';
//start Timer
setInterval(gameTimer.update, 1000);
//make player move again
socket.emit('4');
socket.emit('6');
//make game appear
document.getElementById('gameAreaWrapper').style.opacity = 1;
//play sound
document.getElementById('spawn_cell').play();
//cut 5 cents from account - php function
//CALL PHP FUNCTION HERE WITH AJAX
}
所以 php 文件基本上是 | ../../../../减去5.php |相对于另一个文件。
.PHP：
这是文件：
<?php
session_start();
$servername = "localhost";
$username = "myUser";
$password = "myPass";
$dbname = "myDBname";
$cash_amount = $_SESSION['cash_amount'];
// Create connection
$userid = $_SESSION['id'];
// You must enter the user's id here. /
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
// Fetch the existing value of the cash_amount against that particular user here. You can use the SELECT cash_amount from users where userid = $userid
$_SESSION['cash_amount'] -= 0.05;
$newAmount = $cash_amount - 0.05;
$sql = "UPDATE users SET cash_amount = $newAmount WHERE id = $userid";
$result = $conn->query($sql);
if($result)
{
echo "5 cents have been subtracted!";
}
else
{
echo mysqli_error($conn);
session_start();
session_unset();
session_destroy();
}
$conn->close();
?>
结论：
我如何从函数调用此文件，并且作为奖励：如果我想将 javascript 变量发送到用于更新数据库的文件，我该怎么做？
非常感谢您的帮助！
编写这部分代码 javascript 函数
function countdownEnded() {
/* Your Code */
$.ajax({
type: "POST",
url: '/subtract5.php',
data: { },
success: function (data) {
alert(data);
}
});
}