function windowFormCentered( name, open, winwidth, winheight, param )
{
    var win = null;
    tp=Math.ceil((screen.height-winheight)/2);
    lf=Math.ceil((screen.width-winwidth)/2);
    window.open( open, name, "width="+winwidth+",height="+winheight+",top="+tp+",left="+lf+param+'location=no,status=no,resizable=yes,toolbar=no,scrollbars=1,menubar=no' )
}