spam_secure_email_link.js

// Spamsichere E-Mail-Links (http://www.peterkroener.de/wiki/javascript/mootools/spamsichere_e-mail-links)
(function() {
	var links = $$('span.mail');
	links.each(function(el) {
		var mail = el.get('text').split('[AT]').join('@').split('[PUNKT]').join('.').split('[MINUS]').join('-').replace(/\s/g, '');
		el.set('html', '<a href="mailto:'+ mail +'">'+ mail +'</a>');
	});
})();

spam_secure_email_link.modxsnippet.php

<?php
if(!isset($address)) {
	return '';
}

$search  = array('@',      '.',         '-');
$replace = array(' [AT] ', ' [PUNKT] ', ' [MINUS] ');

return '<span class=mail>'.str_replace($search, $replace, $address).'</span>';
?>