如何在不打开邮件客户端的情况下使用 JavaScript 发送电子邮件？

Question

I'm writing a HTML page with a registration button that should just silently send an email without opening the local mail client. Here is my HTML:

<form method="post" action="">
    <input type="text" id="email_address" name="name" placeholder="Enter your email address..." required>
    <button onclick="sendMail(); return false">Send Email</button>
</form>

... and here is my JavaScript code:

<script type="text/javascript">
  function sendMail() {
    var link = 'mailto:hello@domain.com?subject=Message from '
             +document.getElementById('email_address').value
             +'&body='+document.getElementById('email_address').value;
    window.location.href = link;
}
</script>

The code above works... but it opens the local email client. If I remove the return statement in the onclick attribute like this:

<form method="post" action="">
    <input type="text" id="email_address" name="name" placeholder="Enter your email address..." required>
    <button onclick="sendMail()">Send Email</button>
</form>

... then the email is not sent at all. Am I missing something?

Any help would be reeeally appreciated :-)

Answer 1

You cannot cause the user's browser to send email silently. That would be a horrible security problem as any website could use their system as a spam relay and/or harvest their email address.

You need to make an HTTP request to a server side process (written in the language of your choice) which sends the mail from your server.

Answer 2

You need a server-side support to achieve this. Basically your form should be posted (AJAX is fine as well) to the server and that server should connect via SMTP to some mail provider and send that e-mail.

Even if it was possible to send e-mails directly using JavaScript (that is from users computer), the user would still have to connect to some SMTP server (like gmail.com), provide SMTP credentials, etc. This is normally handled on the server-side (in your application), which knows these credentials.

Answer 3

Directly From Client

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Send an email using only JavaScript

in short: 
1. register for Mandrill to get an API key
2. load jQuery
3. use $.ajax to send an email

Like this -

function sendMail() {
    $.ajax({
      type: 'POST',
      url: 'https://mandrillapp.com/api/1.0/messages/send.json',
      data: {
        'key': 'YOUR API KEY HERE',
        'message': {
          'from_email': 'YOUR@EMAIL.HERE',
          'to': [
              {
                'email': 'RECIPIENT@EMAIL.HERE',
                'name': 'RECIPIENT NAME (OPTIONAL)',
                'type': 'to'
              }
            ],
          'autotext': 'true',
          'subject': 'YOUR SUBJECT HERE!',
          'html': 'YOUR EMAIL CONTENT HERE! YOU CAN USE HTML!'
        }
      }
     }).done(function(response) {
       console.log(response); // if you're into that sorta thing
     });
}

https://medium.com/design-startups/b53319616782

Note: Keep in mind that your API key is visible to anyone, so any malicious user may use your key to send out emails that can eat up your quota.

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Indirect via Your Server - secure

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To overcome the above vulnerability, you can modify your own server to send the email after session based authentication.

node.js - https://www.npmjs.org/package/node-mandrill

var mandrill = require('node-mandrill')('<your API Key>'); 

function sendEmail ( _name, _email, _subject, _message) {
    mandrill('/messages/send', {
        message: {
            to: [{email: _email , name: _name}],
            from_email: 'noreply@yourdomain.com',
            subject: _subject,
            text: _message
        }
    }, function(error, response){
        if (error) console.log( error );
        else console.log(response);
    });
}

// define your own email api which points to your server.

app.post( '/api/sendemail/', function(req, res){

    var _name = req.body.name;
    var _email = req.body.email;
    var _subject = req.body.subject;
    var _messsage = req.body.message;

    //implement your spam protection or checks. 

    sendEmail ( _name, _email, _subject, _message );

});

and then use use $.ajax on client to call your email API.

Answer 4

您不能仅使用客户端脚本来执行此操作...您可以对某些将发送电子邮件的服务器端代码进行 AJAX 调用...

Answer 5

我想你可以使用smtpjs.com

Answer 6

There needs to be some type of backend framework to send the email. This can be done via PHP/ASP.NET, or with the local mail client. If you want the user to see nothing, the best way is to tap into those by an AJAX call to a separate send_email file.

Answer 7

You need to do it directly on a server. But a better way is using PHP. I have heard that PHP has a special code that can send e-mail directly without opening the mail client.

Answer 8

Well, PHP can do this easily.

It can be done with the PHP mail() function. Here's what a simple function would look like:

<?php     
$to_email = 'name@company.com';
$subject = 'Testing PHP Mail';
$message = 'This mail is sent using the PHP mail function';
$headers = 'From: noreply@company.com';
mail($to_email,$subject,$message,$headers);
?>

This will send a background e-mail to the recipient specified in the $to_email .

The above example uses hard coded values in the source code for the email address and other details for simplicity.

Let's assume you have to create a contact us form for users fill in the details and then submit.

1. Users can accidently or intentional inject code in the headers which can result in sending spam mail
2. To protect your system from such attacks, you can create a custom function that sanitizes and validates the values before the mail is sent.

Let's create a custom function that validates and sanitizes the email address using the filter_var() built in function.

Here's an example code:

<?php 
function sanitize_my_email($field) {
    $field = filter_var($field, FILTER_SANITIZE_EMAIL);
    if (filter_var($field, FILTER_VALIDATE_EMAIL)) {
        return true;
    } else {
        return false;
    }
}
$to_email = 'name@company.com';
$subject = 'Testing PHP Mail';
$message = 'This mail is sent using the PHP mail ';
$headers = 'From: noreply@company.com';
//check if the email address is invalid $secure_check
$secure_check = sanitize_my_email($to_email);
if ($secure_check == false) {
    echo "Invalid input";
} else { //send email 
    mail($to_email, $subject, $message, $headers);
    echo "This email is sent using PHP Mail";
}
?>

We will now let this be a separate PHP file, for example sendmail.php .

Then, will use this file on form submission, using the action attribute of the form, like:

<form action="sendmail.php" method="post">
   <input type="text" value="Your Name: ">
   <input type="password" value="Set Up A Passworrd">
   <input type="submit" value="Signup">
   <input type="reset" value="Reset Form">
</form>

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Hope I could help