JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <input type="checkbox" id="chk" data-bind="checked: ok"/><br>
    <input type="button" id="btnCheck" value="Check" onclick="javascript:document.getElementById('chk').checked = true;"/>&nbsp;&nbsp;    
    <input type="button" id="btnUnCheck" value="Uncheck" onclick="javascript:document.getElementById('chk').checked = false;"/> 
</div>
<div>
    Value: <span data-bind="text: ok"></span>    
</div>

JavaScript

function MyViewModel() {
     var self = this;
    
      self.ok = ko.observable();
    
};

var vm = new MyViewModel();
ko.applyBindings(vm);