function ablak_minheight() {
    if( document.body != null )
    {
        var tartalom = document.getElementById('tartalom');

        var ablak_meret = document.body.clientHeight;

        var banner_meret = document.getElementById('banner').offsetHeight;
        var tartalom_meret = document.getElementById('tartalom').offsetHeight;
        var lablec_meret = document.getElementById('lablec').offsetHeight;

        if( ablak_meret > (banner_meret + tartalom_meret + lablec_meret ) )
        {
            var meret = ablak_meret - banner_meret - lablec_meret;
            meret += 40;
            tartalom.style.height = meret + 'px';            
        }
        //alert(ablak_meret + " - " + banner_meret  + " - " +  lablec_meret + " - " + meret );
    }
}