// First, lets avoid those IE 3.x & NN 2.x. The damn from the ancient times...

var IE, NS, browser_ok, on = 1, off = 0, imgOn, imgOff, i;

function init() {

 IE = (document.all) ? 1 : 0;

 NS = (document.layers) ? 1 : 0;

 browser_ok = (IE + NS);

 if (browser_ok) {

  imgOn = new Image();

  imgOff= new Image();

  imgOff.src= "pic/white_dot.gif";

  imgOn.src = "pic/inv_dot.gif";

 }

}

function swap(img, turn) {

  if (! browser_ok) return;

  eval("document."+img+".src=" + ((! turn) ? "imgOn.src" : "imgOff.src"));

}