How to show email addresses on the website to avoid spams?

In the past I have seen this done with javascript. Basically you assign the email address to javascript variables and change the contents of an element using these. You can also provide a fallback for users with javascript disabled which points them in the direction of a form if you need to. Here's an example

var user = 'foo',
    domain = 'bar.com',
    element = document.getElementById('email');

    element.innerHTML = user + '@' + domain;
    //OR
    //'<a href="mailto:' + user + '@' + domain + '">Email</a>'  

This way bots never see the email address as they do not load javascript.

Well, you can figure out a different way every day. Here's one using jQuery.

<a class="mail" href="mailto:[email protected]">e-mail</a>

Then handle the click with jQuery.

$('a.mail').on('click', function(){
    var href = $(this).attr('href');
    $(this).attr('href', href.replace('badmail.', ''));
});

The reason I like this is that I can let the spammers spam the dummy mail domain thinking they got yet another e-mail harvested. If I was maintaining my own spam filter, I could collect samples to my bad bucket.

Also, this approach allows you to render the page quite clean with dynamic data and simply have the javascript snippet only once on the whole site to handle the real user clicks.

Works also on mobiles.

There are multiple different choices for hiding emails on websites, commonly using either the HTML entity version of the email address (as Aziz-Saleh suggested), but from an actual web design point of view, just putting the email address like that on a website isn't the most user friendly thing to do.

For instance, the mailto: link automatically triggers the browser to open the user's Email Application of choice - but consider this. Not everybody has a dedicated email application. For instance, I don't use Outlook (I'm a Windows user), and unless I have Windows Live Mail installed, my computer can't open that link. I think Chrome can open the links into GMail if you're signed in, but I would need to check that.

Ultimately, by using mailto:, you are potentially alienating a portion of your userbase that will not be able to use that link in the first place.

I would suggest using email forms, and there are plenty of easy-to-follow tutorials available for both PHP and your language of JSP, such as this link here: Sending Email in JSP and even on StackOverflow

By using your server to send the email, you get tighter control over how the email is generated, what data the user is allowed to put in, and you could even send them a return email (generated by the server) to confirm that you have received their message. This is a tried-and-tested real-world method of allowing customers and visitors to contact you, whilst still giving you protection and control over the entire process.

TL;DR: Raw mailto: links might alienate people without dedicated email programs, whereas if you use JSP forms, you can control how they contact you, with what information (you can use fields and the HTML5 required attribute to mandate certain input fields) and you can even respond with a do-not-reply email so they know their message was heard (just don't forget to ask for their email address)

The trouble with the JavaScript solutions is that people with JS turned off will also not see the email address. Albeit a minority you need a combination of techniques for the best results.

Many of these techniques are detailed here, but I have provided the solutions only: https://www.ionos.co.uk/digitalguide/e-mail/e-mail-security/protecting-your-e-mail-address-how-to-do-it/

Comments

<p>If you have any questions or suggestions, please write an e-mail to:
us<!-- abc@def -->er@domai<!-- @abc.com -->n.com. 
</p>

Hidden Spans

<style type="text/css">
span.spamprotection {display:none;}
</style>

<p>If you have any questions or suggestions, please write an e-mail to:
user<span class="spamprotection">CHARACTER SEQUENCE</span>@domain.com. 
</p>

Reverse Strings This may not be friendly for multilingual sites.

<style type="text/css">
span.ltrText {unicode-bidi: bidi-override; direction: rtl}
</style>
<p>If you have any questions or suggestions, please write an e-mail to:
<span class="ltrText"> moc.niamod@resu</span>.
</p>

JavaScript as in many other answers

<script type="text/javascript">
var part1 = "user";
var part2 = Math.pow(2,6);
var part3 = String.fromCharCode(part2);
var part4 = "domain.com"
var part5 = part1 + String.fromCharCode(part2) + part4;
document.write("If you have any questions or suggestions, please write an e-mail to:
   <href=" + "mai" + "lto" + ":" + part5 + ">" + part1 + part3 + part4 + "</a>.");
</script>

ROT13 Encryption JavaScript dependant but also helps with GDPR as it's encrypted.

<script type="text/javascript">
function decode(a) {
  return a.replace(/[a-zA-Z]/g, function(c){
    return String.fromCharCode((c <= "Z" ? 90 : 122) >= (c = c.charCodeAt(0) + 13) 
                               ? c : c - 26);
  })
}; 
function openMailer(element) {
var y = decode("znvygb:[email protected]");
element.setAttribute("href", y);
element.setAttribute("onclick", "");
element.firstChild.nodeValue = "Open e-mail software";
};
</script>
<a id="email" href=" " onclick='openMailer(this);'>E-mail: please click</a>

CSS Only Borrowed from here: Protect e-mail address with CSS only

<!doctype html>
<html>
<head>
    <title>Protect e-mail with only css</title>
    <style type="text/css">
        .e-mail:before {
            content: attr(data-website) "\0040" attr(data-user);
            unicode-bidi: bidi-override;
            direction: rtl;
        }
    </style>
</head>
<body>

<span class="e-mail" data-user="nohj" data-website="moc.liamg"></span>

</body>
</html>

Solution 1:

You can use many publicly available email address encoders like (first result on google):

http://www.wbwip.com/wbw/emailencoder.html

This encodes the emails into their character entity value, this will require more logic form scrapers to decode it.

So an email like: [email protected] becomes test@gmail.com which can be used in a mailto as well.

Solution 2:

Use an online email to image converter (again first result on google):

http://www.email2image.com/Convert-Email-to-Image.aspx

To make it as an image. Other services enable you to do this automatically via an API like:

https://www.mashape.com/seikan/img4me-text-to-image-service#!endpoint-Main