browserName = navigator.appName;

browserVer = parseInt ( navigator.appVersion );

version = "n2";

if ( browserName == "Netscape" && browserVer >= 3 ) version = "n3";

if ( browserName == "Microsoft Internet Explorer" && browserVer >=4 ) version = "e4";

if (version == "n3" || version == "e4" ) {
    about_on = new Image ( 95, 29 );
    about_on.src = "images/about_on.gif";
    products_on = new Image ( 112, 29 );
    products_on.src = "images/products_on.gif";
    services_on = new Image ( 112, 29 );
    services_on.src = "images/services_on.gif";
    news_on = new Image ( 97, 29 );
    news_on.src = "images/news_on.gif";
    contact_on = new Image ( 100, 29 );
    contact_on.src = "images/contact_on.gif";
    about_off = new Image ( 95, 29 );
    about_off.src = "images/about_off.gif";
    products_off = new Image ( 112, 29 );
    products_off.src = "images/products_off.gif";
    services_off = new Image ( 112, 29 );
    services_off.src = "images/services_off.gif";
    news_off = new Image ( 97, 29 );
    news_off.src = "images/news_off.gif";
    contact_off = new Image ( 100, 29 );
    contact_off.src = "images/contact_off.gif";
}

function button_on ( imgName ) {
    if ( version == "n3" || version == "e4" ) {
        butOn = eval ( imgName + "_on.src" );
        document [imgName].src = butOn;
    }
}

function button_off ( imgName ) {
    if ( version == "n3" || version == "e4" ) {
        butOff = eval ( imgName + "_off.src" );
        document [imgName].src = butOff;
    }
}