Anti-spamming email harvesting

26 February 2004   0 comments   Web development

Powered by Fusion×

Stu's Site has a nice example of a way of preventing email harvesting by writing the email in reverse and then letting stylesheets reverse it when rendering. The HTML source looks like this:

<style type="text/css">
.backwards {unicode-bidi:bidi-override; direction: rtl;}
<span class="backwards">ku.oc.u7s@uts</span>

And the result is: It works on in my web browsers (win, linux), but the nasty effect is that if you select the text, copy and paste; when you paste it pastes it as ku.oc.u7s@uts. Pretty annoying.

My site uses hex encoding so the HTML looks like this:

<script language="JavaScript">eval(unescape('%64%6F...lots of these...%29'))</script>
<noscript>Peter, mail(at)peterbe dot com</noscript>

The result is as if no anti-harvesting effect had been applied.

Sadly I bet that spammers have tricks to get around both but what matters is how few spammers have yet to come up with the solution. I'm thinking of keeping my method and adding something that scrambles up the encoded string to break spammers regular expressions. But the effect mustn't be as bad as the example on Stu's site.


Your email will never ever be published

Related posts

Bugknits 25 February 2004
What will you not wear today? 27 February 2004
Related by keywords:
Advanced live-search with AngularJS 04 February 2014
mincss "Clears the junk out of your CSS" 21 January 2013
This site is now 100% inline CSS and no bytes are wasted 05 March 2013
\b in Python regular expressions 14 June 2005
UPPER vs. ILIKE 19 April 2010
The importance of checking in Firefox 07 July 2008 incompatible to Mozilla 23 July 2004
Python regular expression tester 19 September 2005
Practical CSS 24 February 2004
Why should I use XHTML? 17 May 2004
10 reasons for web standards 06 June 2004
Regular Expressions in Javascript cheat sheet 18 June 2005