JSFiddle - React, Tailwind, and code Playground

HTML

<select name="#" id="#" onChange="display_div(this.selectedIndex);">
      <option selected="selected"> </option>
      <option >1</option>
      <option >2</option>
      <option >3</option>
</select>

<div id="passenger1" style="display:none;"> hey, 1 works </div>
<div id="passenger2" style="display:none;"> hey, 2 works </div>
<div id="passenger3" style="display:none;"> hey, 3 works </div>

JavaScript

function display_div(e){
   document.getElementById('passenger1').style.display = "none";
   document.getElementById('passenger2').style.display = "none";
   document.getElementById('passenger3').style.display = "none";
   document.getElementById('passenger' + e).style.display = "block";
}