function setHeader(loc, center) {
    var elem, text;

    <!-- set location -->
    elem = document.getElementById("hb_location");
    if(elem) {
        text = document.createTextNode(loc);
        if(elem.hasChildNodes())
            elem.replaceChild(text, elem.firstChild);
        else
            elem.appendChild(text);
    }

    <!-- set center text -->
    elem = document.getElementById("hb_center");
    if(elem) {
        if(center)
            text = document.createTextNode(center);
        else
            text = document.createTextNode("\u00A0");
        if(elem.hasChildNodes())
            elem.replaceChild(text, elem.firstChild);
        else
            elem.appendChild(text);
    }
}

function setHeaderButton(button, image, link) {
    var elem;

    elem = document.getElementById(button);
    if(elem) {
        var a = document.createElement("a");
        a.href=link;
        var img = document.createElement("img");
        img.src = image;
        img.border = "0";
        a.appendChild(img);
        if(elem.hasChildNodes())
            elem.replaceChild(a, elem.firstChild);
        else
            elem.appendChild(a);
    }
}

function setHeaderButton1(image, link) {
    setHeaderButton("hb_button1", image, link);
}

function setHeaderButton2(image, link) {
    setHeaderButton("hb_button2", image, link);
}

function setHeaderButton3(image, link) {
    setHeaderButton("hb_button3", image, link);
}