$(document).ready(function(){
	var xml, select = $('#manufacter-select');

	$.ajax({
		url: "cars.xml",

		success: function(response) {
			xml = $(response);

			xml.find('manufacter').each(function(){			
				var manufacter = $(this),
		    		name = manufacter.children('name').text();

				$('<option/>').text(name).appendTo(select);
		   });
		}
	});

	select.change(function(){
		var manufacterName = $(':selected', this).text(),
			nameTags = xml.find('manufacter > name :contains('+manufacterName+')')
                                      .parent()
                                      .children('cars')
                                      .find('name'),
			names = $.map(nameTags, function(tag){ $(tag).text() });
			
			// do something with names;
	});	
});