Javascript validate human field for contact form

OK, I have tried getting my contact form to work trying to update the php - with no success. Thank you to those of you who attempted to help with my previous question. I now think I should be able to get this to work by updating the JS, but of course I know about as much JS as I do PHP!

So here we go again...

I have a contact form I am using in a Bootstrap responsive single-page site. The form works just fine and sends the emails just fine. My site does not get a whole lot of traffic and I dislike the Captcha fields, so I wanted to insert a simple field for users to enter to ensure they are human. I added a simple math question. Now, I need to know how to validate that the user entered the correct math answer before the email is processed.

My form uses a contact_me.js file in combination with the jqBootstrapBalidation.js file to validate and send the form to the contact_me.php to process the email. I tried updating the PHP (with some suggestions from here) but I could not get it to work. It will always send the email through even if the math answer was entered incorrectly.

It is important to note that I did not write the code for this, I am very new to js. The form and code was supplied by startbootstrap.com templates.

Looking at the contact_me.js field, I can see that it starts off validating the fields with the jqBootstrapBalidation.js. I see it then moves down to a preventDefault and has a comment stating "prevent spam click and default submit behaviour. Is this code already preventing SPAM emails here?

If it is not, I want to force the user to input the correct answer to the math question. I added this field myself. I added the variable for the human field to the contact_me.js file (I assume I needed to do this) to get the value from the form.

Further down on the .js file it then uses ajax to post to the contact_me.php to process the email. Below this is where it looks like it further validates the fields and displays the success/error messages. Is there someplace here I can verify if the user entered the correct math equation (answer should be =5) and if it is correct, then to process the email via the contact_me.php and if the answer is incorrect then to display an error message without sending to the php and ask to try again? Below is the html, contact_me.js and the contact_me.php. Thank you so much for your help with this!

HTML:

 <form name="sentMessage" id="contactForm" novalidate>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label>Name</label>
                            <input type="text" class="form-control" placeholder="Name" id="name" required data-validation-required-message="Please enter your name.">
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label>Email Address</label>
                            <input type="email" class="form-control" placeholder="Email Address" id="email" required data-validation-required-message="Please enter your email address.">
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label>Phone Number</label>
                            <input type="tel" class="form-control" placeholder="Phone Number" id="phone" required data-validation-required-message="Please enter your phone number.">
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label>Message</label>
                            <textarea rows="5" class="form-control" placeholder="Message" id="message" required data-validation-required-message="Please enter a message."></textarea>
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                    <div class="row control-group">
                        <div class="form-group col-xs-12 floating-label-form-group controls">
                            <label>Human</label>
                            <input type="text" class="form-control" placeholder="Two + 3 = ?" id="human" required data-validation-required-message="Please solve math equation to prove you are human">
                            <p class="help-block text-danger"></p>
                        </div>
                    </div>
                     <br>
                    <div id="success"></div>
                    <div class="row">
                        <div class="form-group col-xs-12">
                            <button type="submit" class="btn btn-success btn-lg">Send</button>
                        </div>
                    </div>
                  </form>

contact_me.js:

  $(function() {

$("input,textarea").jqBootstrapValidation({
    preventSubmit: true,
    submitError: function($form, event, errors) {
        // additional error messages or events
    },
    submitSuccess: function($form, event) {
        // Prevent spam click and default submit behaviour
        $("#btnSubmit").attr("disabled", true);
        event.preventDefault();

        // get values from FORM
        var name = $("input#name").val();
        var email = $("input#email").val();
        var phone = $("input#phone").val();
        var message = $("textarea#message").val();
        var human = $("textarea#human").val();
        var firstName = name; // For Success/Failure Message
        // Check for white space in name for Success/Fail message
        if (firstName.indexOf(' ') >= 0) {
            firstName = name.split(' ').slice(0, -1).join(' ');
        }
        $.ajax({
            url: "././mail/contact_me.php",
            type: "POST",
            data: {
                name: name,
                phone: phone,
                email: email,
                message: message,
                human: human
            },
            cache: false,
            success: function() {
                // Enable button & show success message
                $("#btnSubmit").attr("disabled", false);
                $('#success').html("<div class='alert alert-success'>");
                $('#success > .alert-success').html("<button type='button' class='close' data-dismiss='alert' aria-hidden='true'>&times;")
                    .append("</button>");
                $('#success > .alert-success')
                    .append("<strong>Your message has been sent. </strong>");
                $('#success > .alert-success')
                    .append('</div>');

                //clear all fields
                $('#contactForm').trigger("reset");
            },
            error: function() {
                // Fail message
                $('#success').html("<div class='alert alert-danger'>");
                $('#success > .alert-danger').html("<button type='button' class='close' data-dismiss='alert' aria-hidden='true'>&times;")
                    .append("</button>");
                $('#success > .alert-danger').append("<strong>Sorry " + firstName + ", it seems that my mail server is not responding. Please try again later!");
                $('#success > .alert-danger').append('</div>');
                //clear all fields
                $('#contactForm').trigger("reset");
            },
        })
    },
    filter: function() {
        return $(this).is(":visible");
    },
});

$("a[data-toggle=\"tab\"]").click(function(e) {
    e.preventDefault();
    $(this).tab("show");
});
});

// When clicking on Full hide fail/success boxes
$('#name').focus(function() {
$('#success').html('');
});

contact_me.php:

<?php
// Check for empty fields
if(empty($_POST['name'])        ||
empty($_POST['email'])      ||
empty($_POST['phone'])      ||
empty($_POST['message'])    ||
empty($_POST['human'])  ||
!filter_var($_POST['email'],FILTER_VALIDATE_EMAIL))
{
echo "No arguments Provided!";
return false;
}

//Check if simple anti-bot test is correct
if ($human !== 5) {
   $errHuman = 'Your anti-spam is incorrect';
}   

$name = $_POST['name'];
$email_address = $_POST['email'];
$phone = $_POST['phone'];
$message = $_POST['message'];
$message = $_POST['human'];

// Create the email and send the message
$to = 'info@mysite.com'; // Add your email address inbetween the '' replacing yourname@yourdomain.com - This is where the form will send a message to.
$email_subject = "Portfolio Website Message:  $name";
$email_body = "You have received a new message from your portfolio website contact form.\n\n"."Here are the details:\n\nName: $name\n\nEmail: $email_address\n\nPhone: $phone\n\nMessage:\n$message";
$headers = "From: noreply@mysite.com\n"; // This is the email address the generated message will be from. We recommend using something like noreply@yourdomain.com.
$headers .= "Reply-To: $email_address"; 
mail($to,$email_subject,$email_body,$headers);
return true;            
?>

via Chebli Mohamed