function set_opacity()
{
  var opacity = 150;
  var timer ;
  var cas = true ;
  var i = 0;
  var tableau = new Array("<a href=\"http://www.topanalyse.com/index2.php?cas=torrent\"><img src=\"http://img97.imageshack.us/img97/1729/3833c.jpg\" title=\"Image\" /></a>",
  "<a href=\"http://www.topanalyse.com/index2.php?cas=torrent\"><img src=\"http://img686.imageshack.us/img686/3525/yearoneposterus.jpg\" title=\"Image\" /></a>",
  "<a href=\"http://www.topanalyse.com/index2.php?cas=torrent\"><img src=\"http://imagik.fr/uploads/149459\" title=\"Image\" /></a>"
   ,"<a href=\"http://www.topanalyse.com/index2.php?cas=torrent\"><img src=\"http://img23.imageshack.us/img23/4788/sexdrive.png\" title=\"Image\" /></a>",
   "<a href=\"http://www.topanalyse.com/index2.php?cas=torrent\"><img src=\"http://img130.imageshack.us/img130/9340/thetournamen2009.png\" title=\"Image\" /></a>");
  ftg = function(){
		if(opacity >0 && cas == true)
		  {
		   opacity -= 2 ;
		   if(opacity <= 0)
		     {
		     cas = false ;
			 el.innerHTML = tableau[i];
			 i += 1;
			 if(i >=5)
			   i=0 ;
			 }
		  }
		else if(opacity <= 0 || cas == false)
		  {
		   opacity += 2;
		   if(opacity >= 150)
		     cas = true ;
		   }
		   
        el = document.getElementById("pub");
        el.style["filter"] = "alpha(opacity="+opacity+")";
        el.style["-moz-opacity"] = opacity/100;
        el.style["-khtml-opacity"] = opacity/100;
        el.style["opacity"] = opacity/100;
	};
	var timer = setInterval(ftg,100);
        return true;
}