function turnOn(btnName) {
    if(document.images) {
        document.images[btnName].src = "images/button-2.gif";
    }
}

function turnOff(btnName) {
    if(document.images) {
        document.images[btnName].src = "images/button-0.gif";
    }
}

function resize() {
    calculatePositions();
}

// Script for example event goes here
window.onresize = resize;