var url  = document.location.href; 
var title = document.title;
function bookmark() {
    if (window.sidebar) // firefox
        window.sidebar.addPanel(title, url, "");
    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();
    } else if(document.all)// ie
        window.external.AddFavorite(url, title);
}