JSFiddle - React, Tailwind, and code Playground

by psteele

HTML

<div>
    <select data-bind='options: items, value: currentState, optionsText: "state"'></select>
</div>
<div>
    <select data-bind='options: currentState().cities'></select>
</div>

JavaScript

var vm = {
    items: ko.observableArray([
        { state: 'mi', cities: [ 'detroit', 'troy', 'ann arbor' ] },
        { state: 'oh', cities: [ 'toledo', 'sandusky' ] }
        ]),
    currentState: ko.observable()
}

ko.applyBindings(vm);