(function($){
	  // очищаем select
	  $.fn.clearSelect = function() {
	    return this.each(function(){
	      if(this.tagName=='SELECT') {
	        this.options.length = 0;
	        $(this).attr('disabled','disabled');
	      }
	    });
	  }
	  // заполняем select
	  $.fn.fillSelect = function(dataArray) {
	    return this.clearSelect().each(function(){
	      if(this.tagName=='SELECT') {
	        var currentSelect = this;
	        $.each(dataArray,function(index,data){
	          var option = new Option(data.text,data.value);
	          if($.support.cssFloat) {
	            currentSelect.add(option,null);
	          } else {
	            currentSelect.add(option);
	          }
	        });
	      }
	    });
	  }
	})(jQuery);

// выбор автомобиля
	function adjustAuto(){
	  var countryValue = $('#country').val();
	  var tmpSelect = $('#auto');
	  if(countryValue.length == 0) {
	    tmpSelect.attr('disabled','disabled');
	    tmpSelect.clearSelect();
	    adjustModel();
	  } else {
	    $.getJSON(
	      'cascadeSelectAuto.php',
	      {country:countryValue},
	      function(data) {
	        tmpSelect.fillSelect(data).attr('disabled','');
	        adjustModel();
	    });
	  }
	};

// выбор модели
	function adjustModel(){
	  var countryValue = $('#country').val();
	  var autoValue = $('#auto').val();
	  var tmpSelect = $('#model');
	  if(countryValue.length == 0||autoValue.length == 0) {
	    tmpSelect.attr('disabled','disabled');
	    tmpSelect.clearSelect();
	  } else {
	    $.getJSON(
	      'cascadeSelectModel.php',
	      {country:countryValue,auto:autoValue},
	      function(data) {
	        tmpSelect.fillSelect(data).attr('disabled','');
	    });
	  }
	};

$('#country').change(function(){
	  adjustAuto();
	}).change();
$('#auto').change(adjustModel);
$('#model').change(function(){
	  if($(this).val().length != 0) {
	    alert('Выбор сделан!');
	  }
	});