var img1 = new Image();
var img2 = new Image();
var img3 = new Image();
var img4 = new Image();

// preload images
function init() {
      img1.src = "images/pen2.gif";
      img2.src = "images/digital2.gif";
      img3.src = "images/services2.gif";
      img4.src = "images/links2.gif";
}

// highlight a link
function highlight(img) {
      document[img].src = "images/" + img + "2.gif";
}

// unhighlight a link
function unhighlight(img) {
      document[img].src = "images/" + img + ".gif";
}

// find browser version
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 >= 3)
) return 1;
        return 0;
}

// popup window
function displayWindow(url, winName, width, height) {
    var window_width = width;
    var window_height = height;
    var window_top = (screen.height-window_height)/2;
    var window_left = (screen.width-window_width)/2;
    newWindow=window.open(''+ url + '',''+ winName + '','width=' + window_width + ',height=' + window_height + ',top=' + window_top + ',left=' + window_left + ',resizable=yes,scrollbars=no' + '');
    newWindow.focus();
}