img_dir="/Images/";
  function pItem (name, width, height) {
    this.on = new Image();
    this.on.src =img_dir + name + "on.jpg"
    this.off = new Image();
    this.off.src =img_dir + name + "off.jpg"
  }
  function p_new (name) {
    pItem[name] = new pItem(name);
  }
  function img_act (imgName) {
    if (document.images) document[imgName].src = pItem[imgName].on.src;
  }
  function img_inact (imgName) {
    if (document.images) document [imgName].src = pItem[imgName].off.src;
  }
  function load_p (name, num) {
  for (i = 1; i <= num; i++) p_new(name + i);
  }
  if (document.images != null) load_p ('p', 3);