var listy=new Array('p1','p2','p3');


function changetopic(specific) {
   for(var i=0;i<listy.length;i++) {
     hidediv(listy[i]);
	 var itab = listy[i] + 't';
       document.getElementById(itab).className = "";
   }
   showdiv(specific);
   var itab = specific + 't';
     document.getElementById(itab).className = "selected";
}