JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" type="text/css" href="http://extjs.cachefly.net/extjs/4.0.1/resources/css/ext-all.css" />

JavaScript

Ext.application({
    name : 'test',
    launch : function()
     {
        var today = new Date(),
            currYear = today.getFullYear(),
            currMonth = today.getMonth();

       var monthStore = Ext.create('Ext.data.Store', {
            autoLoad : true,
            fields : [
                {name : 'id', type : 'int'}, {name : 'month', type : 'string'}
            ],
            data : [
                {"id" : 0, "month" : "มกราคม"},
                {"id" : 1, "month" : "กุมภาพันธ์"},
                {"id" : 2, "month" : "มีนาคม"},
                {"id" : 3, "month" : "เมษายน"},
                {"id" : 4, "month" : "พฤษภาคม"},
                {"id" : 5, "month" : "มิถุนายน"},
                {"id" : 6, "month" : "กรกฎาคม"},
                {"id" : 7, "month" : "สิงหาคม"},
                {"id" : 8, "month" : "กันยายน"},
                {"id" : 9, "month" : "ตุลาคม"},
                {"id" : 10, "month" : "พฤศจิกายน"},
                {"id" : 11, "month" : "ธันวาคม"}
            ]
        });

        var year = Ext.create('Ext.form.ComboBox', {
            forceSelection : true,
            fieldLabel : 'Choose Year',
            store : [currYear-2, currYear-1, currYear],
            queryMode : 'local',
            renderTo : Ext.getBody(),
            listeners : {
                'change' : function(combo, newvalue, oldvalue)
                {
                    month.lastQuery = null;
                    month.clearValue();
                    if (newvalue == currYear) {
                        month.getStore().filter([
                           Ext.create('Ext.util.Filter', {filterFn: function(item) {return item.get('id') <= currMonth;}})
                        ]);
                                            }
                    else {
                        month.getStore().clearFilter();
                    }
                }
            }
        });
         
        var month = Ext.create('Ext.form.ComboBox', {
           ...