如果我已经有了服务器端代码，如何发送onClick JavaScript电子邮件？

// 引入Nodemailer库
const nodemailer = require('nodemailer');

// 创建邮件发送器
const transporter = nodemailer.createTransport({
  host: 'smtp.example.com',
  port: 587,
  secure: false,
  auth: {
    user: 'your-email@example.com',
    pass: 'your-password'
  }
});

// 创建发送邮件的函数
function sendEmail() {
  // 设置邮件内容
  const mailOptions = {
    from: 'your-email@example.com',
    to: 'recipient@example.com',
    subject: 'Hello from JavaScript',
    text: 'This is a test email sent from JavaScript onClick event.'
  };

  // 发送邮件
  transporter.sendMail(mailOptions, (error, info) => {
    if (error) {
      console.log('Error occurred:', error.message);
    } else {
      console.log('Email sent:', info.response);
    }
  });
}