JSFiddle - React, Tailwind, and code Playground

HTML

<select id="opts" onchange="showForm()">
    <option value="0">Select Option</option>
    <option value="1">Option 1</option>
    <option value="2">Option 2</option>
</select>

<div id="f1" style="display:none">
    <form name="form1">
        <select id="opts" onchange="showForm()">
            <option value="0">Select Option</option>
            <option value="1">Option 1A</option>
            <option value="2">Option 1B</option>
        </select>
    </form>
</div>

<div id="f2" style="display:none">
    <form name="form2">
        <select id="opts" onchange="showForm()">
            <option value="0">Select Option</option>
            <option value="1">Option 2A</option>
            <option value="2">Option 2B</option>
        </select>
    </form>
</div>

<script type="text/javascript">
    function showForm() {
        var selopt = document.getElementById("opts").value;
        if (selopt == 1) {
            document.getElementById("f1").style.display = "block";
            document.getElementById("f2").style.display = "none";
        }
        if (selopt == 2) {
            document.getElementById("f2").style.display = "block";
            document.getElementById("f1").style.display = "none";
        }
        if (selopt == 0) {
            document.getElementById("f2").style.display = "none";
            document.getElementById("f1").style.display = "none";
        }
    }
</script>