JSFiddle - React, Tailwind, and code Playground

HTML

<select name='lang'>
          <option value='en'>English</option>
          <option value='fr'>French</option>
          <option value='sp'>Spanish</option>
        </select>

      <div id="fr" class="page">
        Content of page 1
      </div>
      <div id="en" class="page">
        Content of page 2
      </div>
      <div id="sp" class="page">
        Content of page 3
      </div>

JavaScript

$("select").on('change', function () {
     switch($("select option:selected").val())
     {
         case "en": $("#fr").html("content en");  break;
         case "fr": $("#en").html("content fr");  break;
         case "sp": $("#sp").html("content sp");  break;
     }
});