const done_but = document.getElementById("done");
var logs = []
var xhttp = new XMLHttpRequest();
document.getElementById('r2').checked = true;

done_but.onclick = function() {
  const student = document.getElementById("student-drop").value;
  const face = document.querySelector('input[name="faceses"]:checked').value;
  const time = new Date();

  logs.push([{
    student: student,
    face: face,
    time: time.toUTCString()
  }]);
  xhttp.open("POST", "file:///(file path)/index.html");
  xhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
  xhttp.send(logs);
  console.log(logs);
};

我发现如果你把你的样式和本地js放到你的HTML文件中，你可以把它写到屏幕然后从本地js获取任何输入。要提供服务器数据

var xhttp = new XMLHttpRequest();
xhttp.open("POST", "http://localhost:8000");
xhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
xhttp.send(YourVar);

将vars从js传递到节点

我有一个按钮，按下时我想让它从该js文件发送一个对象（日志）数组到一个节点js文件，然后我可以输出一个JSON文件。我已经尝试了与this tutorial and this one的AJAX，但我仍然不明白如何在js和节点之间传递变量。

const done_but = document.getElementById("done");
var logs = []
var xhttp = new XMLHttpRequest();
document.getElementById('r2').checked = true;

done_but.onclick = function() {
  const student = document.getElementById("student-drop").value;
  const face = document.querySelector('input[name="faceses"]:checked').value;
  const time = new Date();

  logs.push([{
    student: student,
    face: face,
    time: time.toUTCString()
  }]);
  xhttp.open("POST", "file:///(file path)/index.html");
  xhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
  xhttp.send(logs);
  console.log(logs);
};

var xhttp = new XMLHttpRequest();
xhttp.open("POST", "http://localhost:8000");
xhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=UTF-8");
xhttp.send(YourVar);