function popUp(wrapper) { 
  
  var childs = new Array();
  var count = 0;
  for(var n = 0; n<wrapper.childNodes.length; n++) {
    if(wrapper.childNodes[n].nodeType == 1) {
      childs[count] = wrapper.childNodes[n];
      count++;
    }
  }
  var header = childs[0];
  var content = childs[1];
  
  if(content.style.display == "block") {
    header.style.fontWeight = "normal";
    content.style.display = "none";
    wrapper.style.backgroundColor = "transparent";
  }
  else {
    header.style.fontWeight = "bold";
    content.style.display = "block";
    wrapper.style.backgroundColor = "#FFFF99";
  }
}