Ví dụ làm sao tạo form với Google reCAPTCHA v3 sử dụng PHP

In this article, I’m going show you how to add Google reCAPTCHA v3 to a form on your PHP website. The latest reCAPTCHA is different than the previous versions—it doesn’t require user interaction at all. In this post, we'll see how it works, and we’ll build a real-world example for demonstration purposes.

As a website owner, you’re always looking for a strong anti-spam solution which can prevent spamming on your website and only allows legitimate content to come through. Gone are the days when you could integrate a simple text-based CAPTCHA solution and it was enough to stop the naughty bots.

How Google reCAPTCHA v3 Works

It’s said that a picture is worth a thousand words! So let’s have a look at the following screenshot to understand what exactly is going on underneath when you integrate reCAPTCHA v3 on your website.

Let’s try to understand the overall flow in detail:

1. The end user requests a web page.
2. The web app or server returns the requested page, which includes reCAPTCHA v3 code.
3. Next, the user fills in the form and clicks on the submit button.
4. Before submitting the form data to the server, the reCAPTCHA v3 code on the client makes an AJAX call to the Google server and obtains a token. The important thing here is that we have to pass the action attribute with an appropriate value during the AJAX call. You should pass the value which identifies your form. This is the value which you'll use for verification on the server side, along with other parameters.
5. The token obtained in the previous step is submitted along with the other form data. In most cases, we append two hidden variables to the form, token and action, before the form is submitted.
6. Once the form is submitted, we have to perform the verification step to decide if the form is submitted by a human. As a first step, we’ll make a POST request to verify the response token. The POST request passes the token along with the Google secret to the Google server.
7. The response is a JSON object, and we’ll use it to decide if the form is submitted by a human. The format of the JSON object is shown in the following snippet.

[php]your code here[/php]
[css autolinks="false" classname="myclass" collapse="false" firstline="1" gutter="true" highlight="1-3,6,9" htmlscript="false" light="false" padlinenumbers="false" smarttabs="true" tabsize="4" toolbar="true" title="example-filename.php"]your code here[/css]
[code lang="js"]your code here[/code]
[sourcecode language="plain"]your code here[/sourcecode]

[php]your code here[/php]
[css autolinks="false" classname="myclass" collapse="false" firstline="1" gutter="true" highlight="1-3,6,9" htmlscript="false" light="false" padlinenumbers="false" smarttabs="true" tabsize="4" toolbar="true" title="example-filename.php"]your code here[/css]
[code lang="js"]your code here[/code]
[sourcecode language="plain"]your code here[/sourcecode]

[php]your code here[/php]

[php]your code here[/php] [css autolinks="false" classname="myclass" collapse="false" firstline="1" gutter="true" highlight="1-3,6,9" htmlscript="false" light="false" padlinenumbers="false" smarttabs="true" tabsize="4" toolbar="true" title="example-filename.php"]your code here[/css] [code lang="js"]your code here[/code] [sourcecode language="plain"]your code here[/sourcecode]