Add Bookmark - Solved
In case anyone comes across this issue, I changed the behavior from 'onclick' to a javascript in the <a></a> tag:
FROM:
<a href="#"><img src="../webassist/social/icons/favorites.png" onclick="addBookmark(document.title, '<?php echo urlencode('http://www.yourpage.com')" title="Bookmarks" /></a>
TO:
<a href="javascript:addBookmark(document.title, '<?php echo urlencode('http://www.yourpage.com')"><img src="../webassist/social/icons/favorites.png" title="Bookmarks" /></a>
Works in both IE & Firefox (didn't test on other browsers)
Hope it helps
Cecilia M