JSFiddle - React, Tailwind, and code Playground

HTML

<select id="make"></select>
<select id="model"></select>

JavaScript

var carobj;

window.onload = function () {
    var cars = '{"USED":[{"name":"Acura","value":"20001","models":[{"name":"CL","value":"20773"},{"name":"ILX","value":"47843"},{"name":"ILX Hybrid","value":"48964"},{"name":"Integra","value":"21266"},{"name":"Legend","value":"21380"},{"name":"MDX","value":"21422"},{"name":"NSX","value":"21685"},{"name":"RDX","value":"21831"},{"name":"RL","value":"21782"},{"name":"RSX","value":"21784"},{"name":"SLX","value":"21879"},{"name":"TL","value":"22237"},{"name":"TSX","value":"22248"},{"name":"Vigor","value":"22362"},{"name":"ZDX","value":"32888"}]},{"name":"Alfa Romeo","value":"20047","models":[{"name":"164","value":"20325"},{"name":"8c Competizione","value":"34963"},    {"name":"Spider","value":"22172"}]}]}';

    carobj = eval ("(" + cars + ")");
    var makes = document.getElementById('make');

    for (var i = 0; i < carobj.USED.length; i++) {
        var d = carobj.USED[i];
        makes.options.add(new Option(d.name, i));
    }
    
    makes.onchange = getModels;
    getModels();
}

// add models based on make
function getModels () {
    var makes = document.getElementById('make');
    var make = makes.options[makes.selectedIndex].text;
    for (var i = 0; i < carobj.USED.length; i++) {
        if (carobj.USED[i].name == make) {
            var models = document.getElementById('model');
            models.options.length = 0;
            for (var j= 0; j < carobj.USED[i].models.length; j++) {
                var model = carobj.USED[i].models[j];                
                models.options.add(new Option(model.name, j));
            }
            break;            
        }
    }
}