JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-validate/1.13.1/jquery.validate.min.js"></script>
<script src="https://img.infocert.it/js/libphonenumber.js"></script>
<script src="https://img.infocert.it/js/intlTelInput.min.js"></script>
<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/bootstrap/3.3.4/css/bootstrap.min.css">
<script src="//maxcdn.bootstrapcdn.com/bootstrap/3.3.4/js/bootstrap.min.js"></script>

<fieldset id="richiedi">
<form action="" method="POST" name="WebToLeadForm" method="POST" id="WebToLeadForm" class="form-horizontal col-md-11">
<input type="hidden" name="oid">

<p>&nbsp;</p>
<p><b>Per essere contattato da un commerciale</b>, compila il form sottostante. I campi richiesti sono obbligatori.<br /></p>


<div class="form-group">
  <label class="col-md-3 control-label" for="first_name">Nome:</label>
  <div class="col-md-9">
    <input class="form-control" id="first_name" name="first_name" maxlength="40" tabindex="1" type="text">
     <span class="glyphicons form-control-feedback" aria-hidden="true"></span>
  </div>
</div>
 <div class="form-group">
	  <label class="col-md-3 control-label" for="last_name">Cognome:</label>
	 <div  class="col-md-9">
		 <input class="form-control" id="last_name" name="last_name" maxlength="80" tabindex="2" type="text">
		<span class="glyphicons form-control-feedback" ></span>
	 </div>
 </div>
 <div class="form-group">
	  <label class="col-md-3 control-label" for="company">Azienda:</label>
	  <div  class="col-md-9">
	  	<input class="form-control" id="company" name="company" maxlength="40" tabindex="3" type="text">
	  	<span class="glyphicons form-control-feedback" aria-hidden="true"></span>
	  </div>
 </div>

<input type="hidden" name="city" value="">

 <div class="form-group">
	  <label class="col-md-3 control-label" for="state">Provincia:</label>
	  <div  class="col-md-9">



<select class="form-control" id="state" name="state" title="Provincia" tabindex="4">
	<option disabled selected...

JavaScript

$("#phone").intlTelInput({
    //allowExtensions: true,
    //autoFormat: false,
    //autoHideDialCode: false,
    autoPlaceholder: false,
    defaultCountry: "it",
    //ipinfoToken: "yolo",
    //nationalMode: false,
    //numberType: "MOBILE",
    //onlyCountries: ['us', 'gb', 'ch', 'ca', 'do'],
    preferredCountries: ['it'],
    utilsScript: "https://img.infocert.it/js/libphonenumber.js"
  });

var telInput = $("#phone"),
  errorMsg = $("#error-msg"),
  validMsg = $("#valid-msg");

// on blur: validate
telInput.focusout(function() {
  if ($.trim(telInput.val())) {
    if (telInput.intlTelInput("isValidNumber")) {
      validMsg.removeClass("hide");
    } else {
      telInput.addClass("error");
      errorMsg.removeClass("hide");
      validMsg.addClass("hide");
    }
  }
  var numberType = $("#phone").intlTelInput("getNumberType");
  if (numberType == intlTelInputUtils.numberType.MOBILE) {
    // is a mobile number
    $("#phone").attr('name', 'mobile');
  }else{
    $("#phone").attr('name', 'phone');
  }
});

// on keydown: reset
telInput.keydown(function() {
  telInput.removeClass("error");
  errorMsg.addClass("hide");
  validMsg.addClass("hide");
});
$("#text_message").focusout(function(){$("#00Nw00000088clXEAQ").val($("#text_message").val())})
    
    jQuery.validator.addMethod('validatePhone', function() {
			if ($("#phone").intlTelInput("isValidNumber")){
				return true;
				}
			else{
					return false;
				}
				}, "Numero non valido");
				
$(window).load(function()  { 
    $("#WebToLeadForm").validate(  
    {  
        errorElement: 'small', 
	    errorClass: 'help-block',
	    errorPlacement: function(error, element) {
		    if (element.attr("name") == "aut_privacy" ) {
		      error.insertBefore(element.parent());
		    }else {
		      error.insertAfter(element);
		    }
		  },
        rules:  
        {  
        first_name:{  
            required: true,  
            minlength: 2  
            },
        last_name:{  
		    required:...