JSFiddle - React, Tailwind, and code Playground
HTML
<select id="myoptions">
</select>
<input type="button" onclick="alert(document.getElementById('myoptions').selectedIndex)" value="Click here" />
JavaScript
var x = "Jenny,John,Stephanie,Marc,Ryan,Jessica";
var options = x.split(",");
var select = document.getElementById('myoptions');
for(var i=0; i<options.length; i++)
select.options[i] = new Option(options[i], i);