JSFiddle - React, Tailwind, and code Playground

HTML

<form name="selectionForm">
    <select name="states" id="states" size="3" style="width: 150px">
        <option selected>Select a State >></option>
    </select>

    <select name="cities" id="cities" size="3" style="width: 150px"></select>
</form>

JavaScript

jQuery(function($) {
    initCities();
    
    function initCities() {
        var statesAndCities = {
            'Oregon': ['Eugene', 'Portland', 'Salem'],
            'Washington': ['Bellingham', 'Onalaska', 'Seattle']
        };
        
        //populate states
        $.each(statesAndCities,function(k,v){$('#states').append('<option>' + k + '</option>');});
        
        //populate cities
        $('#states').change(function(){
            var $cities = $('#cities');
            $cities.html("");
            var cities = statesAndCities[$(this).val()];
            $.each(cities,function(k,v){$cities.append('<option>' + v + '</option>');});
        });
    }
        
});