JSFiddle - React, Tailwind, and code Playground
HTML
<select id="header-values" multiple="headervalues" style="width:200px" name="headervalues[]" >
<option selected="">MVA</option>
<option>Jet Ski</option>
<option>Bus Accident</option>
<option>Worker's Comp</option>
<option>field1</option>
<option>field2</option>
<option>field3</option>
</select>
<br>
<textarea id="headervalues-log" class="log" class="ui-widget-content"></textarea>
JavaScript
$("#header-values").change(function() {
var selOption = $(this).find(":selected").text();
$("#headervalues-log").text(selOption);
});