prova così:
codice:
<script type="text/javascript">
/* Modified to support Opera */
function bookmarksite(title,url){
if (window.sidebar) // firefox
	window.sidebar.addPanel(title, url, "");
else if(window.external)// ie
	window.external.AddFavorite(url, title);
else if(window.opera && window.print){ // opera
	var elem = document.createElement('a');
	elem.setAttribute('href',url);
	elem.setAttribute('title',title);
	elem.setAttribute('rel','sidebar');
	elem.click();
} 
}
</script>
HTH
Zappa