function MBopenWindow(theURL,winName,features) {
    if (document.all)
        var xMax = screen.width, yMax = screen.height;
    else
        if (document.layers)
            var xMax = window.outerWidth, yMax = window.outerHeight;
        else
            var xMax = xMax, yMax=yMax;

    var xOffset = (xMax - 800)/2, yOffset = (yMax - 600)/2;

    window.open(theURL,winName,'scrollbars=yes,width=800,height=480,screenX='+xOffset+',screenY='+yOffset+',top='+yOffset+',left='+xOffset+'');

}