Select with non-existing value

by Jakub Jedryszek

HTML

<script src="http://cdnjs.cloudflare.com/ajax/libs/knockout/3.2.0/knockout-debug.js"></script>
<p>
    Select a country:
    <select data-bind="options: countries,
                       value: selectedCountry,
                       valueAllowUnset: true"></select>
</p>

<hr />
<h2>Debug</h2>
<div data-bind="text: ko.toJSON($root)"></div>

JavaScript

var viewModel = {
    countries: ['Japan', 'Bolivia', 'New Zealand'],
    selectedCountry: ko.observable(null)
};

ko.applyBindings(viewModel);