function setOverlay () {
    var co = document.getElementById('close-overlay');
    var uo = document.getElementById('unset-overlay');

    Utils.addEvent(co, 'click', closeOverlay );
    Utils.addEvent(uo, 'click', unsetOverlay );
    
    if (hasOverlay) {
        var overlay = document.getElementById('overlay');
        var number  = Utils.readCookie(config_overlay.name) == null ? 0 : Utils.readCookie(config_overlay.name);
        var value   = parseInt(number, 10);
        
        if (value == '-1') 
            return;
        
        if (value >= config_overlay.max)
            return;
        
        Utils.createCookie(config_overlay.name, value+1);
                 
        overlay.style.width = document.body.offsetWidth;
        overlay.style.height = document.body.offsetHeight;    
        overlay.style.visibility = 'visible';
        
        var selects = document.getElementsByTagName('select');
        for (var i=0; i<selects.length; i++) {
            selects[i].style.zIndex = -10000-i;
        }
    }
}

function closeOverlay () {
    document.getElementById('overlay').style.visibility = 'hidden';
    return false;
}

function unsetOverlay () {
    Utils.createCookie(config_overlay.name, config_overlay.max);
    closeOverlay();
    return false;
}

Utils.addEvent(window, 'load', setOverlay);