if (document.images) {
    var onImgArray = new Array()
    onImgArray[1] = new Image
    onImgArray[2] = new Image
    onImgArray[3] = new Image
    onImgArray[4] = new Image
    onImgArray[5] = new Image
    onImgArray[1].src = "images/button_home_active.png"
    onImgArray[2].src = "images/button_plugins_active.png"
    onImgArray[3].src = "images/button_downloads_active.png"
    onImgArray[4].src = "images/button_contacts_active.png"

    var offImgArray = new Array()
    offImgArray[1] = new Image
    offImgArray[2] = new Image
    offImgArray[3] = new Image
    offImgArray[4] = new Image
    offImgArray[5] = new Image
    offImgArray[1].src = "images/button_home.png"
    offImgArray[2].src = "images/button_plugins.png"
    offImgArray[3].src = "images/button_downloads.png"
    offImgArray[4].src = "images/button_contacts.png"
}

function useActiveImage(i) {
    if (document.images) {
        document.images["menu" + i].src = onImgArray[i].src
    }
}

function useInactiveImage(i) {
    if (document.images) {
        document.images["menu" + i].src = offImgArray[i].src
    }
}