if (document.images) {
blogon = new Image(); // Active images
blogon.src = "/images/menu_blog_on.jpg";

blogoff = new Image(); // Inactive images
blogoff.src = "/images/menu_blog.jpg";

porton = new Image(); // Active images
porton.src = "/images/menu_port_on.jpg";

portoff = new Image(); // Inactive images
portoff.src = "/images/menu_port.jpg";

abouton = new Image(); // Active images
abouton.src = "/images/menu_about_on.jpg";

aboutoff = new Image(); // Inactive images
aboutoff.src = "/images/menu_about.jpg";
}

function imgOn(imgName) {

if (document.images) {
document[imgName].src = eval(imgName + "on.src");
}
}

function imgOff(imgName) {
if (document.images) {
document[imgName].src = eval(imgName + "off.src");
}
}