JSFiddle - React, Tailwind, and code Playground

HTML

<textarea id="content" data-bind="value: textareacontent"></textarea><br />
<select id="sel" data-bind="value: selectData">
    <option value="1">value1</option>
    <option value="2">value2</option>
    <option value="3">value3</option>
</select><br />

Selected value is: <span data-bind="text: selectData"></span><br />
Entered text: <span data-bind="text: textareacontent"></span>

JavaScript

var objectData = {
    "textareacontent"   : ko.observable("some random content"),
    "selectData"        : ko.observable("1")
}

ko.applyBindings(objectData);