Wordpress Comment Form Validations

comment-form-validations.php

<?php
/**
 * Post's comment form validation rules
 * Path : wp-content/mu-plugins/comment-form-validations.php
 */
function ans_comment_validation_rules()
{
	if (is_single() && comments_open()) { ?>
		<script type="text/javascript" src="//cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.19.0/jquery.validate.min.js"></script>
		<script type="text/javascript">
			jQuery(document).ready(function ($) {
				$('#commentform').validate({
					rules: {
						author: {
							required: true,
							minlength: 2
						},

						email: {
							required: true,
							email: true
						},

						comment: {
							required: true,
							minlength: 20
						}
					},

					messages: {
						author: "Please provide a name",
						email: "Please enter a valid email address.",
						comment: "Please fill the required field"
					},

					errorElement: "div",
					errorPlacement: function (error, element) {
						element.after(error);
					}

				});
			});    
		</script>
	<?php
	}
}
add_action('wp_footer', 'ans_comment_validation_rules');