JSFiddle - React, Tailwind, and code Playground

HTML

<script src="http://dev.jquery.com/view/trunk/plugins/validate/jquery.validate.js"></script>
 <form class="cmxform" id="commentForm" method="get" action="">
 <fieldset>
   <p>
     <label for="cname">Name</label>
     <em>*</em><input id="cname" name="name" size="25" class="required alphaNumeric" minlength="2" />
   </p>
   <p>
     <input class="submit" type="submit" value="Submit"/>
   </p>
 </fieldset>
 </form>

JavaScript

jQuery.validator.addMethod("alphaNumeric", function (value, element) {
    return this.optional(element) || /^[0-9a-zA-Z]+$/.test(value);
}, "Username must contain only letters, numbers.");

$("#commentForm").validate({
    rules: {
        cname: {
            required: true,
            alphaNumeric: true
        }
    }
});