JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text" />

JavaScript

(function($) {
    $.fn.numeric = function(options) {
        return this.each(function () {
            var $this = $(this);

            $this.blur(function(e) {
                if (isNaN(+this.value)) {
                    $('<span class="error">Must be numeric</span>').insertAfter($this);
                } else {
                    $this.next('span.error').remove();
                }
            });
        });
    };
}(jQuery));
            
$('input').numeric();