Four years ago I started a test to see how well different email obfuscation techniques worked to thwart spammers.
My requirements in order of preference were:
- A clickable link.
- Gracefull degrade for users without javascript.
- Users should be able to copy the email address to the clipboard.
- It should be easy for me to insert an email address on a page.
- It should reduce spam.
Well, it’s been 4 years and here are the results:
| Method (see original post for explanations) | Emails in inbox | percentage of plain text |
|---|---|---|
| Using plain text | 247 | 100% |
| Using AT DOT | 48 | 19% |
| Using AT DOT and javascript to de-obfuscate | 45 | 18% |
| Using code direction | 0 | 0% |
| Using style=”display:none” | 1 | 0% |
| Using ROT13 | 0 | 0% |
These addresses all pointed at Gmail inboxes and Gmail deletes spam after 30 days so the spam folder counts can be ignored.
When I started the experiment I hoped the AT DOT and javascript to de-obfuscate as that seemed to fill most of my requirments but the spammer’s crawlers have obviously cracked that trick (not hard I know). The best solution would seem to be an <a> link using ROT13 and the text of the link either a span using code direction or applying the style to the <a> link itself.
Something like:
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| <p> | |
| email: | |
| <script type="text/javascript"> | |
| // <![CDATA[ | |
| document.write( | |
| "<n uers="znvygb:anzr@qbznva.pbz">".replace(/[a-zA-Z]/g, function(c){return String.fromCharCode((c<="Z"?90:122)>=(c=c.charCodeAt(0)+13)?c:c–26);})); | |
| // ]]> | |
| </script> | |
| <span style="unicode-bidi:bidi-override; direction: rtl">moc.niamod@eman</span> | |
| </a> | |
| </p> |
Messy (and unchecked / written by hand) but I guess an email address will not change much so, once the correct code is worked out, it could be added to a snippet or clipboard manager.