function vlastni_material( policko, tlac ){
  var elem;
  elem = document.getElementById( tlac );
  if( elem.disabled == true ){
    elem.disabled = false;
    elem.className = 'normal_submit';
    document.getElementById( policko + '_f' ).className = 'text_enabled';
    document.getElementById( policko ).disabled = false;
  } else {
    elem.disabled = true;
    elem.className = 'normal_submit_disabled';
    document.getElementById( policko + '_f' ).className = 'text_preskrtnuto';
    document.getElementById( policko ).disabled = true;
  }
}

function prehodit(pol){
  var elem;
  elem = document.getElementById(pol);
  if( elem.disabled == true ){ 
    elem.disabled = false;
    elem.className = 'normal';
    document.getElementById(pol+'_f').className = 'text_enabled';
    document.getElementById(pol+'_f2').className = 'text_enabled';
    document.getElementById(pol+'_s').disabled = false;
    document.getElementById(pol+'_s').className = 'normal_submit';
  } else { 
    elem.disabled = true; 
    elem.className = 'normal_disabled';
    document.getElementById(pol+'_f').className = 'text_disabled';
    document.getElementById(pol+'_f2').className = 'text_disabled';
    document.getElementById(pol+'_s').disabled = true;
    document.getElementById(pol+'_s').className = 'normal_submit_disabled';
  }
}
function iniciace_checkboxy(pole, pole2, pole3){
  var i;
  for( i in pole ){
    if( document.getElementById(pole[i]).checked == false ){ 
      document.getElementById(pole2[i]).className = 'normal_disabled';
      document.getElementById(pole2[i]).disabled = true;
      document.getElementById(pole2[i]+'_s').disabled = true;
      document.getElementById(pole2[i]+'_s').className = 'normal_submit_disabled';
      document.getElementById(pole3[i]).className = 'text_disabled';      
      document.getElementById(pole3[i]+'2').className = 'text_disabled';      
    }
  }
}
function zmena_obr( x, y, obr_id ){
  var max = 150;
  var vysl;
  var nx;
  var ny;
  var cx = document.getElementById(x).value;
  var cy = document.getElementById(y).value;
  var nx2;
  var ny2;
   
  
  if( cy == 0 ){ 
    vysl = 1;
  } else {
    vysl = cx / cy;  
  }
  
  if( vysl < 1 ){
    ny = max;
    nx = Math.round( vysl * max );    
  } else {
    nx = max;
    ny = Math.round( max / vysl );
  }

  nx2 = (170-nx)/2; 
  ny2 = (170-ny)/2; 
  
  document.getElementById('i1_1').width = nx2;
  document.getElementById('i1_1').height = ny2;
  document.getElementById('i1_2').width = nx2;
  document.getElementById('i1_2').height = ny2;
  document.getElementById('i1_3').width = nx2;
  document.getElementById('i1_3').height = ny2;
  document.getElementById('i1_4').width = nx2;
  document.getElementById('i1_4').height = ny2;
  document.getElementById('i2_1').width = nx;
  document.getElementById('i2_1').height = ny2;
  document.getElementById('i2_2').width = nx; 
  document.getElementById('i2_2').height = ny2;
  document.getElementById('i3_1').width = nx2;
  document.getElementById('i3_1').height = ny;
  document.getElementById('i3_2').width = nx2;
  document.getElementById('i3_2').height = ny;
  document.getElementById(obr_id).width = nx;
  document.getElementById(obr_id).height = ny;

}

var pruh = 1;
/*
function tr( trida, pole ){
  var output;
  for( var i = 0; i < pole.length; i ++ ){
    output = output + "<td class=" + trida + pruh + ">" + pole[i] + "</td>";
  } 
  pruh ++;
  if( pruh > 2 ) pruh = 1;
  return "<tr>" + output + "</tr>";
}*/