JSFiddle - React, Tailwind, and code Playground

HTML

<select id="dropdown">
    <option value="1">One</option>
    <option value="2">Two</option>
    <option value="3">Three</option>
</select>
<input id="textField" type="text" value="2" />

JavaScript

(function() {
    var dropdown$ = $('#dropdown'),
        textField$ = $('#textField');
    
    function changeVal() {
        var val = parseInt(textField$.val());
        if(!!val && val > 0 && val < 4) {
            dropdown$.val('One');
        }
    }
    
    textField$.on('keyup', changeVal);
    
    changeVal();
})();