JSFiddle - React, Tailwind, and code Playground
HTML
<h4>Country</h4>
<select name="filter_country" id="filterCountryId">
<option></option>
<option >argentina</option>
<option>australia</option>
<option>brazil</option>
<option>china</option>
<option>germany</option>
<option>japan</option>
<option>newzealand</option>
<option>russia</option>
<option>southafrica</option>
<option>uk</option>
<option>uruguay</option>
<option>us</option>
<option>usa</option>
</select>
JavaScript
$('#filterCountryId').on('change', function() {
alert( this.value ); // or $(this).val()
});