JSFiddle - React, Tailwind, and code Playground

HTML

<input type='text' id='res' />
<br/>
<select id='aa'>
    <option value='normal'>Normal</option>
    <option value='low'>Low</option>
    <option value='high'>High</option>
</select>

JavaScript

var result = $('#res');
var aa = $('#aa');

result.on('keydown keyup', function () {
    if (result.val() < 90) {
        $('option[value="low"]', aa).prop('selected', true);
    } else if (result.val() > 90) {
        $('option[value="high"]', aa).prop('selected', true);
    }
});