[devote]

<select id="_make">
  <option value="">- Марка -</option>
</select>
<select id="_model">
  <option value="">- Модель -</option>
</select>
<select id="_country">
  <option value="">- Страна -</option>
</select>
<script>
var goods = [
  {
    name: {
      ru:'МТЗ',
      ua: 'МТЗ'
    },
    model: '82.1',
    country: {
      ru:'Беларусь',
      ua: 'Білорусь'
    },
    price: '1.11',
    images: 'img/belarus/mtz/МТЗ_82.1.jpeg'
  },
  {
    name: {
      ru:'МТЗ',
      ua: 'МТЗ'
    },
    model: '82.1',
    country: {
      ru:'Россия',
      ua: 'Россия'
    },
    price: '1.11',
    images: 'img/belarus/mtz/МТЗ_82.1.jpeg'
  },
  {
    name: {
      ru:'МТЗ2',
      ua: 'МТЗ2'
    },
    model: '82.12',
    country: {
      ru:'Беларусь',
      ua: 'Білорусь'
    },
    price: '1.11',
    images: 'img/belarus/mtz/МТЗ_82.1.jpeg'
  },
  {
    name: {
      ru:'МТЗ3',
      ua: 'МТЗ3'
    },
    model: '82.13',
    country: {
      ru:'Беларусь',
      ua: 'Білорусь'
    },
    price: '1.11',
    images: 'img/belarus/mtz/МТЗ_82.1.jpeg'
  }
];

var language = 'ru';

function updateSelect(elem, list) {
  var _default = elem.children[0];
  while(elem.firstChild) {
    elem.removeChild(elem.firstChild);
  }
  elem.appendChild(_default);
  if (list) {
    for(var key in list) {
      if (list.hasOwnProperty(key)) {
        var option = document.createElement('option');
        option.innerHTML = option.value = key;
        elem.appendChild(option);
      }
    }
  }
  return elem;
};

(function(goods, language) {
  var _make = document.getElementById('_make');
  var _model = document.getElementById('_model');
  var _country = document.getElementById('_country');

  var optionsData = {};
  for(var i = 0; i < goods.length; i++) {
    var _vName = goods[i].name[language];
    var _vModel = goods[i].model;
    var _vCountry = goods[i].country[language];
    optionsData[_vName] = optionsData[_vName] || {};
    optionsData[_vName][_vModel] = optionsData[_vName][_vModel] || {};
    optionsData[_vName][_vModel][_vCountry] = optionsData[_vName][_vModel][_vCountry] || {};
  }

  updateSelect(_make, optionsData).onchange = function() {
    updateSelect(_model, optionsData[_make.value]).onchange();
  };
  _model.onchange = function() {
    updateSelect(_country, (optionsData[_make.value]||{})[_model.value]);
  }
})(goods, language);
</script>