<script type="text/javascript">    
//<![CDATA[    
function getBrowserInfo() {    
var t,v = undefined;    
if (window.opera) t = 'Opera';    
else if (document.all) {    
t = 'IE';    
var nv = navigator.appVersion;    
var s = nv.indexOf('MSIE')+5;    
v = nv.substring(s,s+1);    
}    
else if (navigator.appName) t = 'Netscape';    
return {type:t,version:v};    
}    

function bookmark(a){    
var url = window.document.location;    
var title = window.document.title;    
var b = getBrowserInfo();    
if (b.type == 'IE' && 7 > b.version && b.version >= 4) window.external.AddFavorite(url,title);    
else if (b.type == 'Opera') {    
a.href = url;    
a.rel = "sidebar";    
a.title = url+','+title;    
return true;    
}    
else if (b.type == "Netscape") window.sidebar.addPanel(title,url,"");    
else alert("Нажмите CTRL-D, чтобы добавить страницу в закладки.");    
return false;    
}    
//]]>    
</script>

<a href="javascript:void(0);" onclick="return bookmark(this);">Добавить в избранное</a>