JSFiddle - React, Tailwind, and code Playground

by Joe

HTML

<select name="dropdown1" id="#dropdown11">
  <option></option>
  <option value="1">Test 1</option>
  <option value="2">Test 2</option>
  <option value="3">Test 3</option>
</select>

<select name="dropdown2" id="#dropdown22">
  <option></option>
  <option value="1">Test 1</option>
  <option value="2">Test 2</option>
  <option value="3">Test 3</option>
</select>

JavaScript

var $('#dropdown11') = $("select[id='#dropdown11']");
var $('#dropdown22') = $("select[id='#dropdown22']");
$dropdown1.change(function() {
    var selectedItem = $(this).val();
    var $options = $("select[name='dropdown1'] > option").clone();  
    $("select[name='dropdown2']").html($options);
    $("select[name='dropdown2'] > option[value="+selectedItem+"]").remove();  
});