Add to favorites effect implemented by js code and compatible with mainstream browsers_javascript skills

//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; 
 
   
}