function openHelpWindow(id)
{

    height = 100;
    width = 400;
    TOP = (screen.height-height)/2;
    LEFT = (screen.width-width)/2;
    
    var win = window.open('categories_help.php?id=' + id, 'HelpWindow',
        'innerHeight=' + height + ',innerWidth=' + width +
        ',height=' + height + ',width=' + width +
        ',top=' + TOP + ',left=' + LEFT +
        ',location=no,menubar=no,resizable=no,scrollbars=yes');
    if(window.focus) win.focus();
}