const contactFormSubmit = () => {
    const submitButton = document.querySelector('#contact-submit');
    console.log(submitButton);
    document.addEventListener('click', e => {
      if (e.target == submitButton) {
        e.preventDefault();
        const name = document.getElementById('name').value;
        const email = document.getElementById('email').value;
        const message = document.getElementById('message').value;
        checkForm(name, email, message);
      }
    })
  }

const checkForm = (name, email, message) => {
    if (name && message && email) {
      if (/^w+([.-]?w+)*@w+([.-]?w+)*(.w{2,3})+$/.test(email)) {

        jQuery.ajax({
           url: `<?php echo admin_url('admin-ajax.php'); ?>`,
           type: "POST",
           cache: false,
           data:{
              action: 'send_email',
              name: name,
              email: email,
              message: message,
                },
           success:function(res){
                   alert("Email Sent.");
                  }
        });

    printMessage('success', 'Thank you for you email. We will get back to you as soon as we can');
  } else {

    printMessage('error', 'email is not in the correct form')
  }
} else {
  printMessage('error', 'Make Sure all fields are filled out')
  }
 }

const printMessage= (outcome, message) => {
    if (!messageOn) {
      resultMessageContainer = document.createElement('div');
      pageContent = document.querySelector('.contact-container');
      document.body.insertBefore(resultMessageContainer, pageContent);
    } else {
      resultMessageContainer.innerHTML = '';
    }

    if (outcome == 'success') {
      resultMessageContainer.innerHTML = `${outcome} ${message}`;
      console.log('SUCCESS');
      messageOn = true;
    } else if (outcome == 'error') {
      resultMessageContainer.innerHTML = `${outcome} ${message}`;
      console.log('failure');
      messageOn = true;
    }
  }

jquery.min.js:4 POST http://elbe.local/contact-us/%3C?php%20echo%20admin_url(%27admin-ajax.php%27);%20?%3E 404 (Not Found)

add_action( 'wp_ajax_send_email', 'callback_send_email' );
add_action( 'wp_ajax_nopriv_send_email', 'callback_send_email' );

function callback_send_email(){

      $name = $_REQUEST['name'];
      $email = $_REQUEST['email'];
$message= $_REQUEST['message'];
$subject = "Contact Form";
  $email_body = "The following prospectus has contacted you.<br>".
    "Name: $name. <br>".
    "Email: $email. <br>".
    "Message: $message. <br>";
      $to = "naderabouezze93@gmail.com";
      $headers  = "MIME-Version: 1.0" . "rn";
      $headers .= "Content-type:text/html;charset=UTF-8" . "rn";
      $headers .= "From: $name <$email> rn";
      $headers .= "Reply-To: $email rn";
  $mail = mail($to,$subject,$email_body,$headers);
    if($mail){
          echo "Email Sent Successfully";
        }
die();