JSFiddle - React, Tailwind, and code Playground

HTML

<form name="userparkrating" action="userparkreview.php?park_id=<?=$park_id?>" onsubmit="return validateForm()" method="post">
            <input class="rb0" id="Ans_1" name="rating" type="radio" value="0" checked="checked" />                       
            <label for="Ans_1">0</label>
            <input class="rb2" id="Ans_3" name="rating" type="radio" value="1" />
            <label for="Ans_3">1</label>
            <input class="rb4" id="Ans_5" name="rating" type="radio" value="2" />    
            <label for="Ans_5">2</label>
            <input class="rb6" id="Ans_7" name="rating" type="radio" value="3" />
            <label for="Ans_7">3</label>
            <input class="rb8" id="Ans_9" name="rating" type="radio" value="4" />
            <label for="Ans_9">4</label>
            <input class="rb10" id="Ans_11" name="rating" type="radio" value="5" />
            <label for="Ans_11">5</label>


    <br/>
    <input type="submit" value="Submit Rating" name="submit"/>

</form>

JavaScript

function validateForm() {
    var ratings=document.forms["userparkrating"]["rating"];
    var rating = 0;
    for (var i = 0; i < ratings.length; i++) {
        if (ratings[i].checked) {
            rating = ratings[i].value;
        }
    }
if (not(0<rating && rating<=5))
  {
      alert("You must rate this park before submitting");
      return false;
  }
  return true;
}