cur=null;
function showPopup(id) {
  var event=window.event || arguments.callee.caller.arguments[0]; 
  hideCurrentPopup();
  var el=document.getElementById(id);
  if(el) {
    var scrollY,scrollX;
    if(document.documentElement && document.documentElement.scrollTop)
      scrollY=document.documentElement.scrollTop;
    else
       scrollY=document.body.scrollTop;
    if(document.documentElement && document.documentElement.scrollLeft)
      scrollX=document.documentElement.scrollLeft;
    else
       scrollX=document.body.scrollLeft;
    el.style.top=(scrollY+event.clientY)+'px';
    el.style.left=(scrollX+event.clientX)+'px';
    el.style.display='block';
    cur=el;
    document.onclick=hideCurrentPopup;
  }
  event.cancelBubble=true;
  return false;
}

function hideCurrentPopup() {
  if(cur!=null)
    cur.style.display='none';
  document.onclick=null;
}