The function above takes three arguments when called: the three components of every email address (i.e., username, domain name, and top level domain name.) The first line defines the function name, you should change this if you're going to use it in a production environment. The next two lines point the script to the location of your "@" and "." image files. Lines 3-7 are used to put the string "mailto:" into the "cmd" variable in such a way that it would be difficult for a harvester to guess that it was hiding a mailto link. Line 8 adds the username to the string.

Line 9 adds "%40" to the string. This is the html character-set equivalent of "@", real browsers will interpret this as an "@" symbol; most harvesters will not. Lines 10 and 11 add the domain, the "." and the top-level domain name to the string. Line 12 ends the function by wrapping the code necessary to make an HTML link around our string, creating an image-based visible email address and returning the entire concoction to the calling function.

Using the code
To test, place the createAd function in the JS Header element of a Domino form or page, or in the head section of a standard HTML page. Next, somewhere in the main body of the Web page, include the following line:

<script language="JavaScript"> document.write(createAd('myuser','domain','com')) </script>

Replace the strings for the user name, domain and top level domain names in each instance with the values of the email address you want returned. If you use a computed text element for this, you can have each of the 3 variables computed whenever the page or form is opened.

If you use all of the techniques I have described in concert, you will be amazed at how little spam reaches your primary email accounts--assuming those accounts are not already out in circulation. This is much easier to achieve with new email addresses then those that are already known to spammers.

I'm working on a future article about how to block spam that's already making its way to your Domino servers.

Daniel Koffler works as a Domino consultant for major organizations in North America and Europe, specializing in network design, security analysis and knowledge management, he is also the author of several OpenSource projects.