var pics = 4,

    pic_prefix = 'pic',

    pic_path   = 'pic/m',

    pic_ext_act  = '_1.gif',

    pic_ext_pass = '.gif';

var img_cache = new Array(pics * 2);



var is_loaded=0;



function loaded() {

  var i, j;



  if (is_loaded)

    return true;

    

  is_loaded = 1;



  for (i = 1, j = 0; i <= pics; i++) {

    img_cache[j] = new Image();

    img_cache[j++].src = pic_path + i + pic_ext_pass;



    img_cache[j] = new Image();

    img_cache[j++].src = pic_path + i + pic_ext_act;

  }



  return true;

}



function hilite(img_no, state) {

  if (!is_loaded || !(document.images[pic_prefix + img_no]))

    return false;



  document.images[pic_prefix + img_no].src = img_cache[(img_no - 1)* 2 + state].src;

  return false;

}