JSFiddle - React, Tailwind, and code Playground

JavaScript

function checkRequired(e) {
    var valid = true, v, name;
    type = $(e).attr('type');
    if (type == 'radio') {
        name = $(e).attr('name');
        v = $("input[name='" + name + "']:checked").val();
        if (!v) {
            $("." + name + "_error").addClass("error");
            valid = false;
        }
    }
    if (type == 'text') {
        name = $(e).attr('name');
        v = $(e).val();
        if (!v) {
            $("." + name + "_error").addClass("error");
            $("#" + name).addClass("input_error");
            valid = false;
        }
    }
    if (type == 'file') {
        name = $(e).attr('name');
        v = $(e).val();
        if (!v) {
            $("." + name + "_error").addClass("error");
            $("#" + name).addClass("input_error");
            valid = false;
        }
    }
    if (type == 'select') {
        name = $(e).attr('name');
        v = $(e).val();
        if (!v) {
            $("." + name + "_error").addClass("error");
            $("#" + name).addClass("input_error");
            valid = false;
        }
    }
    return valid;
}

function checkEmail(e) {
    var valid = true, v, type;
    type = $(e).attr('type');
    if (type == 'text') {
        name = $(e).attr('name');
        v = $(e).val();
        if (v == '') {} else {
            if (!isEmail(v)) {
                $("." + name + "_error").addClass("error");
                $("#" + name).addClass("input_error");
                valid = false;
            }
        }
    }
    return valid;
}

function isEmail(v) {
    var filter = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i
    if (filter.test(v)) {
        return true;
    } else {
        return false;
    }
}

function isNumeric(v) {
    if (v.match(/^\d+$/) == null) return false;
    return true;
}
$.fn.clearForm = function () {
    return this.each(function () {
        var type = this.type,
            tag = this.tagName.toLowerCase();
        if (tag...