JSFiddle - React, Tailwind, and code Playground

HTML

<select id="first">
    <option value="0" selected>No</option>
    <option value="1">Yes</option>
</select>

<select id="second">
    <option value="0">No</option>
    <option value="1" selected>Yes</option>
</select>

JavaScript

var first = document.getElementById('first');
var second = document.getElementById('second');

var handler = function () {
    var invertedValue = this.value === '0' ? 1 : 0;
    if (this === first) {
        second.value = invertedValue;
    } else {
        first.value = invertedValue;
    }
};

first.addEventListener('change', handler, false);
second.addEventListener('change', handler, false);