JSFiddle - React, Tailwind, and code Playground

HTML

<select name="webmenu" id="webmenu" onChange='clickedFunction(this.value);'>
    <option value="" id="No_button" selected>Select a value</option>
    <option value="UK" id="UK_button" title="assets/images/uk_flag.png">&nbsp;United Kingdom</option>
    <option value="US" id="US_button" title="assets/images/us_flag.png">&nbsp;United States</option>
    <option value="EU" id="EU_button" title="assets/images/euro_flag.png">&nbsp;Europe</option>
</select>

JavaScript

clickedFunction = function (val) {
    console.log(val);
    switch (val) {
        case 'US':
            finalResultsUS();
            break;
        case 'UK':
            finalResultsUK();
            break;
        case 'EU':
            finalResultsEuro();
            break;
    }
};

finalResultsUS = function() {
    alert('You clicked on US');
};
finalResultsUK = function() {
    alert('You clicked on UK');
};
finalResultsEuro = function() {
    alert('You clicked on EU');
};