homeon = new Image();
homeon.src = "images/home_on.gif";
homeoff = new Image();
homeoff.src = "images/home_off.gif";

abouton = new Image();
abouton.src = "images/about_on.gif";
aboutoff = new Image();
aboutoff.src = "images/about_off.gif";

serviceson = new Image();
serviceson.src = "images/services_on.gif";
servicesoff = new Image();
servicesoff.src = "images/services_off.gif";

projectson = new Image();
projectson.src = "images/projects_on.gif";
projectsoff = new Image();
projectsoff.src = "images/projects_off.gif";

joinon = new Image();
joinon.src = "images/join_on.gif";
joinoff = new Image();
joinoff.src = "images/join_off.gif";

contacton = new Image();
contacton.src = "images/contact_on.gif";
contactoff = new Image();
contactoff.src = "images/contact_off.gif";

// On function
function imgAct(imgName) {
    document[imgName].src = eval(imgName + "on.src");
}

// Off function
function imgInact(imgName) {
    document[imgName].src = eval(imgName + "off.src");
}