JSFiddle - React, Tailwind, and code Playground

HTML

<div id="frontContent">

        <p id ="levelContent">Levels: </p>
        <form id="levelSelection">
            <input type="radio" name="level" value="1"  >Level 1</input>
            <input type="radio" name="level" value="2" checked='true'>Level 2</input>
        </form>

            <p id="startButton"><a href="index.html">Start</a></p>

        <p id ="scoreBoard">Highest Score: <span id="score">0</span></p>

</div>

<script>
    
    var radios = document.getElementsByName('level');
        alert(radios.length);
for (var i = 0, length = radios.length; i < length; i++) {
    if (radios[i].checked) {
        alert(radios[i].value);
        break;
    }
}
    
</script>