var last_selected = '';
function hilite_me(boton) {
  if (document.all) { // ie.
    obj = document.all.item(boton);
    obj.style.background = "#FFFFCC";
    if (last_selected != '') {
      obj = document.all.item(last_selected);
      obj.style.background = "transparent";
    };
  }
  else if (document.getElementById) { // ns7.
    obj = document.getElementById(boton);
    obj.style.background = "#FFFFCC";
    if (last_selected != '') {
      obj = document.getElementById(last_selected);
      obj.style.background = "transparent";
    };
//  }
//  else if (document.layers) {
//    obj = document.layers[boton];
//    obj.bgcolor = "white";
//    if (last_selected != '') {
//      obj = document.layers[last_selected];
//      obj.bgcolor = "transparent";
//    };
  };
  
  last_selected = boton;
};