function show_or_hide( obj, h_size ) {
    if( 'block' == document.getElementById(obj).style.display )
        {document.getElementById(obj).style.display = 'none';
        window.moveBy(0,  1-(h_size / 2) );
        window.resizeBy(0, 1 - h_size ); }
    else
       {document.getElementById(obj).style.display = 'block';
        window.moveBy(0,  (h_size / 2) );
        window.resizeBy(0, h_size ); }
}