JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://knockoutjs.com/downloads/knockout-2.2.1.js"></script>
<div>   
    <select data-bind="options: values, value: option, optionsCaption: 'Selecione...', event: { click: onClickSelect }" ></select>
    <label data-bind="text: option"></label>    
</div>

JavaScript

var ViewModel = {
    option : ko.observable(),
    values : ko.observableArray()
};

ViewModel.onClickSelect = (function() {  
    //Simulate server side 
    setTimeout(function()
               {
                   ViewModel.values(["one", "two", "three"]);
               }, 2000);
    
});
 
ko.applyBindings(ViewModel);