function click(e)
{
    if (!e)
        e = window.event;
    if ((e.type && e.type == "contextmenu") || (e.button && e.button == 2) || (e.which && e.which == 3))
    {
        if (window.opera)
            window.alert("This function is deactivated.");
        return false;
    }
}
if (document.layers)
    document.captureEvents(Event.MOUSEDOWN);
document.onmousedown = click;
document.oncontextmenu = click;