Yes, I am YOUNG.

/***********************************************
* Bookmark site script- © Dynamic Drive DHTML code library (www.dynamicdrive.com) 
* This notice MUST stay intact for legal use 
* Visit Dynamic Drive at http://www.dynamicdrive.com/ for full source code 
***********************************************/ 
/* Modified to support Opera */

function bookmarksite(title,url) { 
   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); 
} 

출처: http://blog.daum.net/hometip/1734946