JSFiddle - React, Tailwind, and code Playground

HTML

<form>

    <input type="checkbox" id="c01" name="01" />
    <input type="checkbox" id="c02" name="02" />
    <input type="checkbox" id="c03" name="03" />

    <input value="03,01," />

</form>

JavaScript

$(":checkbox").change(function() {
        var csv = $(":checkbox:checked").map(function() {
            return this.id;
        }).get().join(",");
        alert(csv);
        $("input:hidden").val(csv);
    });