如何通过将值JavaScript传递给PHP来获取PHP中的URL值？

var value = "example";
var url = "example.php";

// 使用XMLHttpRequest对象发送POST请求
var xhr = new XMLHttpRequest();
xhr.open("POST", url, true);
xhr.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xhr.onreadystatechange = function() {
  if (xhr.readyState === 4 && xhr.status === 200) {
    // 请求成功后的处理逻辑
    console.log(xhr.responseText);
  }
};
xhr.send("value=" + value);

// 或者使用fetch API发送POST请求
fetch(url, {
  method: "POST",
  headers: {
    "Content-Type": "application/x-www-form-urlencoded"
  },
  body: "value=" + value
})
.then(function(response) {
  if (response.ok) {
    return response.text();
  }
  throw new Error("Network response was not ok.");
})
.then(function(data) {
  // 请求成功后的处理逻辑
  console.log(data);
})
.catch(function(error) {
  // 请求失败后的处理逻辑
  console.log(error);
});

$value = $_POST['value'];
echo $value;