在Div中显示ReCaptcha错误消息

I have been trying to figure out how to show a error message (Please try captcha again) in a div with php.

Here is the HTML page:

<link href="css/bootstrap.min.css" rel="stylesheet">
<link href="css/bootstrapValidator.min.css" rel="stylesheet">
<link rel="stylesheet" href="css/style.css">


<script src='https://www.google.com/recaptcha/api.js'></script> 





<div class="container">

<form class="well form-horizontal" action="contact.php" method="post"  id="contact_form">
<fieldset>

<!-- Form Name -->
<legend>Contact Us Today!</legend>

    <!-- To Whom Select -->

      <div class="form-group">
        <label class="col-md-4 control-label">Send To*</label>
        <div class="col-md-4 selectContainer">
          <div class="input-group"> <span class="input-group-addon"><i class="glyphicon glyphicon-list"></i></span>
            <select id="sendTo" name="sendTo" class="form-control selectpicker" >
             <option value=" ">Select Who To Email</option>
             <option id="sb" value="sb">Stephanie</option>
             <option id="mb" value="mb">Michael</option>
             <option id="questions" value="questions">Questions</option> 
            </select>
          </div>
        </div>
      </div>

    <!-- Text input-->

    <div class="form-group">
      <label class="col-md-4 control-label">First Name</label>  
      <div class="col-md-4 inputGroupContainer">
      <div class="input-group">
      <span class="input-group-addon"><i class="glyphicon glyphicon-user"></i></span>
      <input  name="fullname" placeholder="Full Name" class="form-control"  type="text">
        </div>
      </div>
    </div>

    <!-- Text input-->
           <div class="form-group">
      <label class="col-md-4 control-label">E-Mail</label>  
        <div class="col-md-4 inputGroupContainer">
        <div class="input-group">
            <span class="input-group-addon"><i class="glyphicon glyphicon-envelope"></i></span>
      <input name="email" placeholder="E-Mail Address" class="form-control"  type="text">
        </div>
      </div>
    </div>

    <!-- Text area -->

    <div class="form-group">
      <label class="col-md-4 control-label">Project Description</label>
        <div class="col-md-4 inputGroupContainer">
        <div class="input-group">
            <span class="input-group-addon"><i class="glyphicon glyphicon-pencil"></i></span>
                <textarea class="form-control" name="comment" placeholder="Project Description"></textarea>
      </div>
      </div>
    </div>

   <!-- Captcha -->

   <div class="form-group">
      <label class="col-md-4 control-label">Captcha</label>
      <div class="col-md-4 inputGroupContainer">
       <div class="g-recaptcha" data-sitekey="SITE KEY #"></div>
     </div>
  </div>

   <!-- Error message -->
   <div class="errorMessage"><?php echo $err_message; ?> </div>

   <!-- Button -->
   <div class="form-group">
     <label class="col-md-4 control-label"></label>
     <div class="col-md-4">
       <button type="submit" class="btn btn-warning" >Send <span class="glyphicon glyphicon-send"></span></button>
     </div>
   </div>

  </fieldset>
  </form>

 </div><!-- /.container -->


<script src="js/jquery-3.1.1.min.js"></script>
<script src="js/bootstrap.min.js"></script>
<script src="js/bootstrapvalidator.min.js"></script>
<script src="js/index.js"></script>

Now here is the php page with code to verify captcha is either false or true. I have tested this and it does work if captcha isn't entered it redirects to a page showing the message and if is verity (true) will send email.

This is the part that verity the captcha response false or true: PHP Page:

<?php
session_start();
/**
* This example shows settings to use when sending via Google's Gmail servers.
*/

//SMTP needs accurate times, and the PHP time zone MUST be set
//This should be done in your php.ini, but this is how to do it if you don't have access to that
date_default_timezone_set('Etc/UTC');   

//Contact Form Data
$fullnameField = $_POST['fullname'];
$emailField = $_POST['email'];
$commentsField = $_POST['comment'];

$secret="SECRET KEY #";
$response=$_POST["g-recaptcha-response"];
$verify=file_get_contents("https://www.google.com/recaptcha/api/siteverify?secret={$secret}&response={$response}");
$captcha_success=json_decode($verify);

if ($captcha_success->success==false) {
 echo "<p>You are a bot! Go away!</p>";
 }
 else if ($captcha_success->success==true) {
       (code to send mail using phpMailer)
 }

Everything works right when I fill out form and recaptcha and click send , email is sent. Now when I don't click on recaptcha box and hit send it close's page but shows a page with the text You are a bot! Go away! I know that is what ECHO does, except I don't want that, I would like to be able to put the error message in the errorMessage div on the HTML page. I have tried $err_message = 'Recaptcha Failed. Please try again' and echo $err_message = 'Recaptcha Failed. Please try again' except neither one of these works either. I am also using a js file to validate the 3 fields, name, email and comment. Any help on this would be great. Have searched all over the internet and haven't come across a solution yet.