JSFiddle - React, Tailwind, and code Playground

HTML

<font size="3">State:</font>
  <select name="State">
    <option value="PA" selected>PA</option>
    <option value="NJ">NJ</option>
    <option value="NY">NY</option>
    <option value="DE">DE</option>
  </select>

JavaScript

var elems = document.getElementsByTagName('select');
    elems[0].value = 'DE';