var imgHomeOn = new Image();
var imgHomeOff = new Image();
var imgTouchOn = new Image();
var imgTouchOff = new Image();
var imgMeetOn = new Image();
var imgMeetOff = new Image();
var imgPressOn = new Image();
var imgPressOff = new Image();
var imgBooksOn = new Image();
var imgBooksOff = new Image();

imgHomeOn.src = "img/nav_home_on.gif";
imgHomeOff.src = "img/nav_home.gif";
imgTouchOn.src = "img/nav_touch_on.gif";
imgTouchOff.src = "img/nav_touch.gif";
imgMeetOn.src = "img/nav_meet_on.gif";
imgMeetOff.src = "img/nav_meet.gif";
imgPressOn.src = "img/nav_press_on.gif";
imgPressOff.src = "img/nav_press.gif";
imgBooksOn.src = "img/nav_books_on.gif";
imgBooksOff.src = "img/nav_books.gif";

function fShow(strDiv) {
        document.getElementById(strDiv).style.visibility = "visible";
        document.getElementById(strDiv).style.display = "block";
}

function fHide(strDiv) {
        document.getElementById(strDiv).style.visibility = "hidden";
        document.getElementById(strDiv).style.display = "none";
}


function fToggle(strID) {
        if(document.getElementById(strID).style.visibility == "hidden") {
                fShow(strID);
        } else {
                fHide(strID);
        }
}