transformar script php em javascript

Não sei qual dos dois lugares é o certo então vou postar aqui.

Eu gostaria de saber se tem como fazer esse código aqui só q em Javascript ou ajax? É um código usando o API do mailchimp para newsletter só que eu preciso mostrar ele na página que não tem suporte php, só javascript.

Formulário:

<?php session_start(); ?>
<?php
 $statusMsg = !empty($_SESSION['msg'])?$_SESSION['msg']:'';
 unset($_SESSION['msg']);
 echo $statusMsg;
?>

<form method="post" action="action.php">
 <p><label>First Name: </label><input type="text" name="fname" /></p>
 <p><label>Last Name: </label><input type="text" name="lname" /></p>
 <p><label>Email: </label><input type="text" name="email" /></p>
 <p><input type="submit" name="submit" value="SUBSCRIBE"/></p>
</form>

	Código:

<?php
session_start();
if(isset($_POST['submit'])){
 $fname = $_POST['fname'];
 $lname = $_POST['lname'];
 $email = $_POST['email'];
 if(!empty($email) && !filter_var($email, FILTER_VALIDATE_EMAIL) === false){
 // MailChimp API credentials
 $apiKey = 'InsertMailChimpAPIKey';
 $listID = 'InsertMailChimpListID';

 // MailChimp API URL
 $memberID = md5(strtolower($email));
 $dataCenter = substr($apiKey,strpos($apiKey,'-')+1);
 $url = 'https://' . $dataCenter . '.api.mailchimp.com/3.0/lists/' . $listID . '/members/' . $memberID;

 // member information
 $json = json_encode([
 'email_address' => $email,
 'status' => 'subscribed',
 'merge_fields' => [
 'FNAME' => $fname,
 'LNAME' => $lname
 ]
 ]);

 // send a HTTP POST request with curl
 $ch = curl_init($url);
 curl_setopt($ch, CURLOPT_USERPWD, 'user:' . $apiKey);
 curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
 curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
 curl_setopt($ch, CURLOPT_TIMEOUT, 10);
 curl_setopt($ch, CURLOPT_CUSTOMREQUEST, 'PUT');
 curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
 curl_setopt($ch, CURLOPT_POSTFIELDS, $json);
 $result = curl_exec($ch);
 $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
 curl_close($ch);

 // store the status message based on response code
 if ($httpCode == 200) {
 $_SESSION['msg'] = '<p style="color: #34A853">You have successfully subscribed to CodexWorld.</p>';
 } else {
 switch ($httpCode) {
 case 214:
 $msg = 'You are already subscribed.';
 break;
 default:
 $msg = 'Some problem occurred, please try again.';
 break;
 }
 $_SESSION['msg'] = '<p style="color: #EA4335">'.$msg.'</p>';
 }
 }else{
 $_SESSION['msg'] = '<p style="color: #EA4335">Please enter valid email address.</p>';
 }
}

// redirect to homepage header('location:index.php');