if(!window.console)
window.console = { log: function(message) {} };

Event.observe(window, 'load', function() {
    
    $$('#topnavi td.navpoint').each(function(cell) {
        var area  = cell.id.split('_')[1];
        
        var link  = $('navlink_' + area);
        var image = $('navimg_'  + area).cloneNode(true);
        
        var actImage = new Image();
        actImage.src = 'images/' + area + '_a.gif';
        actImage.border = 0;
        
        Event.observe(link, 'mouseover', function() { $('navimg_'+area).src = actImage.src; })
        Event.observe(link, 'mouseout', function()  { $('navimg_'+area).src = image.src; })
    });
});