var url = new Object();
url['home'] = 'content.php?page=normal&id=172';
url['bedrijf'] = 'content.php?page=normal&id=173';
url['port'] = 'content.php?page=normal&id=174';
url['contact'] = 'content.php?page=normal&id=176';
url['extra'] = 'content.php?page=normal&id=219';

var activebutton = "home";

function buttonover(name)
{
    var newImage = "pix/" + name + "over.gif";
    document[name].src = newImage;
}

function buttonout(name)
{
    if (name == activebutton) return;
    var oldImage = "pix/" + name + ".gif";
    document[name].src = oldImage;
    
}

function buttonclick(name)
{
    var preactivebutton = activebutton; 
    activebutton = name;
    buttonout(preactivebutton);
    window.focus();
    window.parent.content.location = url[name];
}