节点 Js + JS 输入 = document.getElementById-PHP中文网问答

有一个节点 JS 脚本（app.js），用于向邮件发送一封信：

const { response } = require("express");
const express = require("express");
const nodemailer = require("nodemailer");
const app = express();
const port = 5000;

//
function sendEmail(tel) {
  return new Promise((resolve, reject) => {
    var tranporter = nodemailer.createTransport({
      service: "gmail",
      auth: {
        user: ,
        pass: ,
      },
    });
    const mail_configs = {
      from: "myEmail",
      to: "artemdvd@mail.ru",
      subject: "Testing Koding 101 Email",
      text: "tel",
    };
    tranporter.sendMail(mail_configs, function (error, info) {
      if (error) {
        console.log(error);
        return reject({ message: "An error has occured" });
      }
      return resolve({ message: "Email sent succesfuly" });
    });
  });
}

app.get("/", (req, res) => {
  sendEmail()
    .then((response) => res.send(response.message))
    .catch((error) => res.status(500).send(error.message));
});

app.listen(port, () => {
  console.log(`nodemailerProject is listening at http://localhost:${port}`);
});

其他js文件中有一个按钮，它运行这个js脚本并在我按下按钮时发送电子邮件：

let input = document.getElementById("phonenumber");

head.addEventListener("click", function () {
  fetch("http://localhost:5000/")
    .then((response) => response.json())
    .then((data) => console.log(data))
    .catch((error) => console.error(error));
});

html 文件中有一个用于文本消息的输入字段

如何在按下按钮时通过电子邮件发送此输入值？