The script will work across all browsers implementing the w3c DOM and has additionally been written to work under the following DTDs: html 4.01, xhtml 1.0, and xhtml 1.1. It's got one glaring limitation: as stated, it can only convert a single email address due to the use of document.getElementById(), but you get the idea. Additionally, it can of course be rewritten to obfuscate any number of email addresses on a web-page.
It's using a kind of generalised ROT-13 for the coding mechanism, which of course means that,
In order for the script to work, the <body> tag has to be modifyed to call the script, and the email link has to be written in a special way:
<body onload="decode('wsx')"> <a id="wsx" title="LeWWZVcULMN90GMT9MNT9D"></a>
The above is how my email address has been encoded on this very page. If you look at the source html code for the page, you'll see this.