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CAPTCHA is a simple test to determine if a user is a computer or a human. It is used to prevent spam abuse on the websites. So if you use PHP CAPTCHA on your web site forms, this can help in stopping some bots and making life harder for other bots in accessing or using your forms. In brief the CAPTCHA protection works by generating a random string, writing it to an image, then storing the string inside of a session or by some other method. This is then checked when the form is submitted.

When allowing users to enter data into our website, we’d like to see whether the info is entered by the human. Otherwise, people will use robots to push the majority of unwanted data into the web site. By allowing malicious access, it’ll cause tons of problems. for instance, XSS attack or SQL injection and more. Sometimes it’ll increase server load and let it down. it’s going to annoy your regular users thanks to the unavailability of the web site. Captcha is one among the simplest remedies for this hazard. It prevents anonymous access and stops robots from sending data.

We need to create 4 files

ajax_captcha.js // This file process ajax post for form.
captcha.php // This will check if captcha submitted is valid or not
create_image.php // This file will create an image from session string
index.php // This is demo file, will show a captcha image and form to test

Demo: PHP AJAX CAPTCHA

So, here we go:

Captcha element in Javascript

Validating Captcha code in server-side

PHP code to create captcha

Output Captcha element in HTML contact form

Download Fullcode:

https://yyen.info/rRjMrLlFZB

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Last updated on August 26th, 2020 at 06:09 am

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