$(document).ready(function() {
	
	$('#lista_nivel_1').change(
	function() {
		changeSelect('lista_nivel_2');
		$('#lista_nivel_3').html('');
	});
	$('#lista_nivel_2').change(
	function() {
		changeSelect2('lista_nivel_3');
	});		
});

function changeSelect(area){
	var id_area = $('#lista_nivel_1 option:selected').val();
	$.ajax({
		  url: document.URL,
		  data: "select=lista_nivel_2&padre="+id_area,
		  type: "GET",		      
	      dataType: "json",
		  success: function(result) {
			var html = '';
			html +='<option value="-1">-- Todos --</option>';
			$.each(result, function(i,item){
				html +='<option value="'+i+'">' + item + '</option>';
			});
			//alert(html);
		    $('#lista_nivel_2').html(html);
		    //alert('Load was performed.');
		  }
		});
}

function changeSelect2(area){
	var id_area = $('#lista_nivel_2 option:selected').val();
	$.ajax({
		  url: document.URL,
		  data: "select=lista_nivel_3&padre="+id_area,
		  type: "GET",		      
	      dataType: "json",
		  success: function(result) {
			var html = '';
			html +='<option value="-1">-- Todos --</option>';
			$.each(result, function(i,item){
				html +='<option value="'+i+'">' + item + '</option>';
			});
			//alert(html);
		    $('#lista_nivel_3').html(html);
		    //alert('Load was performed.');
		  }
		});
}