var agt=navigator.userAgent.toLowerCase();
function addToFavorite(favTitle){
  if ((navigator.appVersion.indexOf("MSIE") > 0) && (agt.indexOf("mac")== -1)) {
    window.external.AddFavorite("http://www.sweetronics.com", unescape(favTitle));
  }else{
  alert("Sorry this feature isn't supported by your browser. To bookmark the site use Ctrl + D on a PC or Apple + D on a Mac")
}}