How to filter values to come inside list box which are integers only

[#1]

Currently I am having a dropdown which contains items when i choose one item from dropdown there is a list box which gets populated with list of items corresponding to the item choosen from dropdown. But I want only those items should come inside list box whose value is real means it should be number..

This is my javascript

$(document).ready(function() {

    $.ajax({

        url: "avb.json",

        dataType: "json",

        success: function(obj) {

            console.log("obj--", obj)

            var jsObject = obj;

            var usedNames = [];

            $('<option>', {

                text: 'Select your Option',

                value: '',

                selected: 'selected',

                disabled: 'disabled',

                location: 'fixed'

            }).appendTo('#dropdown1')

            $.each(obj, function(key, value) {

                if (usedNames.indexOf(value.name) == -1) {

                    $("#dropdown1").append("<option value=" + key + ">" + value.name + "</option>");

                    usedNames.push(value.name);

                }

            });

            $('#dropdown1').change(function() {

                $('#listbox').toggle(this.value != "");

            });

            $('#dropdown1').change(function() {

                $('#listbox').empty();

                $('<option>', {

                    text: 'Select your List Option',

                    value: '',

                    selected: 'selected',

                    disabled: 'disabled'

                }).appendTo('#listbox');

                var selection = $('#dropdown1 :selected').text();

                console.log("as".selection);

                $.each(jsObject, function(index, value) {

                    console.log("%o",value)

                    if (value['name'] == selection) {

                        var optionHtml = '';

                        for (var i = 1; i <=20; i++) {

                            var attr = 'attr' + ('000' + i).substr(-3);

                            var val = 'val' + ('000' + i).substr(-3);

                            optionHtml += '<option value="' + attr + '" data-val="'+value[val]+'">' + value[attr] + '</option>';

                        }

                        $("#listbox").css("width", "500px")

                        $("#listbox").css("height", "300px")

                        $('#listbox').append(optionHtml);

                        return false;

                    }

                    var selectedOption = $(this).find('option:selected');

                    console.log(selectedOption);

                });

            });

            $("#listbox").on("click", function() {

                console.log("asd", $('#listbox option:selected').attr('data-val'));

                var zxv =  $('#listbox option:selected').attr('data-val')

                $(".bar").attr("y",zxv)

                console.log("test", $(".bar").attr("y",zxv))

            //   $(".bar").attr("height",'100')

            })

        }

    });

});

[#2]

Hi Jasmin,

You can change the settings into Integer by following image.