function fix_mw (feld,def) {
    var v = parseInt(String(feld.value).replace(/\D/g,''));
    if (isNaN(v)) v = def;
    if (v < def) v = def;
    feld.value = v;
  }
  
  function fix_sw (feld) {
    var v = parseInt(String(feld.value).replace(/\D/g,''));
    if (isNaN(v)) v = 1;
    if (v < 1) v = 1;
    feld.value = v;
  }