JSFiddle - React, Tailwind, and code Playground

HTML

<form>
<input type="checkbox" id="pizza" name="pizza" value="yes"> <label for="pizza">
I would like to order a</label>
<select name="pizza_kind" id="pizza_kind">
    <option>(choose one)</option>
    <option value="margaritha">Margaritha</option>
    <option value="hawai">Hawai</option>
</select>
pizza.
</form>

JavaScript

var update_pizza = function () {
    if ($("#pizza").is(":checked")) {
        $("#pizza_kind").removeAttr("disabled");
    }
    else {
        $("#pizza_kind").attr('disabled', 'disabled');
    }
};

$(update_pizza);
$("#pizza").change(update_pizza);