JSFiddle - React, Tailwind, and code Playground

HTML

<p>  
    <select class="mobile-vendor">
    <option value="motorola">Motorola</option>
    <option value="nokia">Nokia</option>
    <option value="android">Android</option>
  </select>

<select class="model">
    <option></option>
</select>
</p>
<p><a id="download-link" href="#" style="display: none;">Download it here</a></p>

CSS

#download-link {
    padding: 13px 15px 13px 15px;
    font-size: larger;
    font-decoration: underline;
    background-color: #ffffbb;
    border: 2px dashed red;
    margin-top: 16px;
    display: inline-block;
}

JavaScript

$(function() {
    var selectValues = {
        "nokia": {
            "N97": "http://www.google.com",
            "N93": "http://www.stackoverflow.com"
        },
        "motorola": {
            "M1": "http://www.ebay.com",
            "M2": "http://www.twitter.com"
        }
    };

    var $vendor = $('select.mobile-vendor');
    var $model = $('select.model');
    $vendor.change(function() {
        $model.empty().append(function() {
            var output = '';
            $.each(selectValues[$vendor.val()], function(key, value) {
                output += '<option>' + key + '</option>';
            });
            return output;
        });
    }).change();

    // bonus: how to access the download link
    $model.change(function() {
        $('#download-link').attr('href', selectValues[$vendor.val()][$model.val()]).show();
    });
});