Using a simple obfuscating script on your website’s published email
addresses can reduce the amount of email spam by 90% or more. Email spam
primarily comes from email harvesting bots, similar to search engine
bots, that scour the internet looking for email addresses to spam. There
are several ways to obfuscate email addresses.
Common methods to obfuscate email addresses:
- Encoding
- Javascript
- Flash
- Using an Image instead of text
Javascript and Flash obfuscation basically create a
text version of your email that cannot be read by all but the most
complex email harvesting robots. These methods work well at stopping
email harvesting (Flash is far better than Javascript), but your
visitors must have flash installed or javascript enabled for these to
work or they too cannot see your email address.
Example of what a Javascript email would look like to a computer. (From: seowebsitepromotion.com)
<script type="text/javascript">
//<![CDATA[
var email = "questions"
var domain = "ecommerce-blog.org"
document.write("" + email + "@" + domain + "")
//]]>
</script>
These can also be called externally or through an action script which is even more effective.
Images of an email address can be used in place of
text. While this is probably as effective at stopping spam as flash and
Javascript, it completely prevents copying the text. This makes it very
annoying to try and email the site owner as contact addresses are often
long and can be complex. Users are very prone to mis-entering email
characters and this generally leads to frustration and annoyance by
everyone. I recommend not using this method.
Encoding is by far my preferred method of email
obfuscation. While it is not as effective as the other methods, it stops
the majority of spambots. It does not create browser compatibility or
usability issues. It is as easy to use as copying and pasting some html
onto a web-page when it is being created.
Encoding can be done with a hex, decimal, and others. HTML interprets
these encoded characters as the ones we see and read. This way your
visitors sees an A while a computer sees an
A.
Some good encoding tools:
http://www.ianr.unl.edu/email/encode/ – This is a simple and very effective encoding generator.
http://www.ianr.unl.edu/email/encode/ – This is a simple and very effective encoding generator.
http://www.seowebsitepromotion.com/obfuscate_email.asp This script offers a variety of encoding and javascript obfuscation techniques.
Email Obfuscation Comparison:
| Method | Usability | Effectiveness | Difficulty |
| Flash | Bad | Extremely Good | Hard |
| Javascript | Ok | Very Good | Medium |
| Image | Bad | Very Good | Medium |
| HTML Encoding | Great | Good | Easy |
