function getAppVersion() {
		appname= navigator.appName;
		appversion = navigator.appVersion;
		majorver = appversion.substring(0, 1); 
		if ( (appname == "Netscape") && ( majorver >= 3 ) ) return 1;
		if ( (appname == "Microsoft Internet Explorer") && (majorver >= 4) ) return 1;
        return 0;
}

function swtch(num, imgname) {
        if (getAppVersion())
                imgname.src = img[num].src;
}
imgsrc = new Array();
imgsrc[0]  = "images/bott.gif";
imgsrc[1]  = "images/botta.gif";
imgsrc[2]  = "images/bott2.gif";
imgsrc[3]  = "images/bott2a.gif";
imgsrc[4]  = "images/bott3.gif";
imgsrc[5]  = "images/bott3a.gif";

if (getAppVersion()) {
        img = new Array();
        for (i = 0; i < imgsrc.length; i++) {
                img[i] = new Image();
                img[i].src = imgsrc[i];
        }
}