var isNav4, isIE4;
if (parseInt(navigator.appVersion.charAt(0)) >= 4) {
isNav4 = (navigator.appName == "Netscape") ? 1 : 0;
isIE4 = (navigator.appName.indexOf("Microsoft") != -1) ? 1 : 0;
}
function fitWindowSize() {
if (isNav4) {
window.innerWidth = document.layers[0].document.images[0].width;
window.innerHeight = document.layers[0].document.images[0].height;
}
if (isIE4) {
window.resizeTo(640, 480);
width = 640 - (document.body.clientWidth -  document.images[0].width);
height = 480 - (document.body.clientHeight -  document.images[0].height);
window.resizeTo(width, height);
   }
}