var levelArray = new Array();

function expandcollapse(index, postid) { 
   var whichpost = document.getElementById(postid);
   if (levelArray.length > index) {
	   if (levelArray[index] != null) {
	   	levelArray[index].className="hiddenDIV";
	   }
   }
   if (levelArray.length >= index) levelArray[index] = whichpost;
   if (whichpost.className=="shownDIV") { 
      whichpost.className="hiddenDIV"; 
   } else { 
      whichpost.className="shownDIV"; 
   } 
}