Adding favorites to js code and compatible with mainstream browsers

//加入收藏 function AddFavorite(){   if (document.all) {   addToBookMark(window.location.href, document.title);   } else if (window.sidebar) {   addToBookMark(document.title, window.location.href);   } }  function addToBookMark(url,title){  var ua = navigator.userAgent.toLowerCase();  if(ua.indexOf("msie 8")>-1){   external.AddToFavoritesBar(url,title);//IE8  }else{  try {   window.external.addFavorite(url, title);  } catch(e) {    try {       window.sidebar.addPanel(title, url);//firefox      } catch(e) {       alert("加入收藏失败，请使用Ctrl+D进行添加");      }    }  }  return false;     }