JSFiddle - React, Tailwind, and code Playground

HTML

<input type="radio" name="IsPercentageBased" value="IsPercentageBased" data-bind="checked: IsPercentageBased"/>
<span>Percentage</span>

<input type="radio" name="IsPercentageBased" value="IsPercentageBased" data-bind="checked: IsPercentageBased"/>
<span>Value</span>


<input data-bind = "value: Value, valueUpdate: 'afterkeydown', disable: IsPercentageBased() == 'true'"></input>

JavaScript

function ViewModel(){
    var self = this;
    
    self.IsPercentageBased = ko.observable();
    self.Value = ko.observable();    
}.

ko.applyBindings(new ViewModel());