Add custom captcha to comment form

Question

I have a blog for my official website. I allow people for commenting on my blog but i don't want to get comment from auto-bot. Therefore, i am thinking of to add an extra field which is called "security question" to the comment form. But i don't know how to make it work.

This is the code i have for processing my existing contact form. (contact_info_submit.php)

<?php

$name = $_POST['name'];
$phone = $_POST['phone'];
$email = $_POST['email'];
$location = $_POST['location'];
$purpose = $_POST['purpose'];
$status = $_POST['status'];
$findus = $_POST['findus'];
$inquiry = $_POST['inquiry'];
$security = $_POST['security'];
$from = "JT Design";
$to = "inquiry@jtdesign.my";
$subject = "$from, $name has submitted the enquiry form.";
$message = "Hi $from,\n$name has submitted the enquiry form. Details are as follow: \n\n/*** Form Details Begin ***/\n\nName: $name\nPhone Number: $phone\nEmail Address: $email\nLocation: $location\nContact Purpose: $purpose\nHouse Status: $status\nHow did visitor find us?: $findus\nMessage: $inquiry\n\n/*** Form Details Ended ***/\n\nPlease response to $name as soon as possible.\n\nRegards,\n$from";

if ($security=="17") {
   mail($to, $subject, $message, "From: JTDesiGn");
   header("Location:/thanks.php");
}

else {
   header("Location:/enquiry-form/?Submission=failed");
}
?>

Url to see my online enquiry form: www.jtdesign.my/enquiry-form/

Any solution to apply this code to wordpress comment form? I want to add the "security" field only.

Answer 1

Use this SI CAPTCHA Anti-Spam plugin, may be helpful to you

https://wordpress.org/plugins/si-captcha-for-wordpress/screenshots/

Answer 2

Here is exmaple code,You will change as per your requirement

Put this in your HTML

<INPUT class="input" type="text" name="vercode" value="" required>                                     
<img src="captcha.php" style="margin:3px 0px; width:110px; height:34px">

Create Captcha File captcha.php

<?php 
session_start(); 
$text = rand(10000,99999); 
$_SESSION["vercode"] = $text; 

$image = imagecreatefromjpeg("images/bg.jpg");
$txtColor = imagecolorallocate($image, 0, 0, 0);
imagestring($image, 5, 5, 5, $text, $txtColor);
header("Content-type: image/jpeg");
imagejpeg($image);
?>

than use this code

<?php 
session_start(); 
if ($_POST["vercode"] != $_SESSION["vercode"] OR $_SESSION["vercode"]=='')  { 

     echo  '<strong>Incorrect verification code...</strong>'; 
}
else
{
    $name = $_POST['name'];
$phone = $_POST['phone'];
$email = $_POST['email'];
$location = $_POST['location'];
$purpose = $_POST['purpose'];
$status = $_POST['status'];
$findus = $_POST['findus'];
$inquiry = $_POST['inquiry'];
$from = "JT Design";
$to = "inquiry@jtdesign.my";
$subject = "$from, $name has submitted the enquiry form.";
$message = "Hi $from,\n$name has submitted the enquiry form. Details are as follow: \n\n/*** Form Details Begin ***/\n\nName: $name\nPhone Number: $phone\nEmail Address: $email\nLocation: $location\nContact Purpose: $purpose\nHouse Status: $status\nHow did visitor find us?: $findus\nMessage: $inquiry\n\n/*** Form Details Ended ***/\n\nPlease response to $name as soon as possible.\n\nRegards,\n$from";

if ($security=="17") {
   mail($to, $subject, $message, "From: JTDesiGn");
   header("Location:/thanks.php");
}

else {
   header("Location:/enquiry-form/?Submission=failed");
}
}
?>