What is New in PHP Contact Us Script

User must enter data in the name field, email, subject, and message before submitting
The new version contains more user input filtering. So it keeps the script safe. We sanitize each input key and value using the function htmlspecialchars() and the filter FILTER_SANITIZE_STRING. And I strip any HTML code or invalid characters.

Introduction

Run out-of-box PHP contact-us script, it does not need modification, it will detect the domain and send an email containing the contact message to info@exmple.com whatever fields are in your form; it will detect them and send the form data with email.

System Requirements

Any website with hosting supports PHP; Almost all hosts do support it.
In other words, you could use it for any website regardless of what it uses: pure HTML/PHP, WordPress, Joomla, Drupal, or any other system

PHP Version

PHP 5.6 / PHP 7.0 / PHP 7.1 / PHP 7.2 / PHP 7.3 / PHP 7.4 / PHP 8.0 / PHP 8.1 / PHP 8.2

Background

Lots of contact-us scripts are available over the internet. On the other hand, other scripts need modification of the PHP file before use while this script will run directly out of the box.
So this script is very useful to those who do not know PHP and to beginners of PHP.

Using the Code

Unzip the downloaded zip file
Then create the contact-us folder in the www directory of your website
After that, upload the files to the contact-us folder
and that is all.
Finally, the contact-us URL is like example.com/contact-us replace example.com with your domain

Modifying contact-us Form Design

You could modify the Contact Us page design as you want
Add or omit fields as needed
Use from_email, from_name, subject, message and captcha as fields names
Put your Ads or make your form free of ads
You are free to put a link to us or not.

About the contact-us Code

From Action

<form action="send.php" method="POST">

Fields Names

Use from_email, from_name, subject, message and captcha as main fields' names in your form.

Captcha

If you don’t wish to use a captcha, then change the 1^st line of the ‘config.php’ code to be as follows:

$captcha = false;

If you wish to use a captcha, then no change is needed and the 1^st line of the ‘config.php’ code will be as follows:

$captcha = true;

If you need to modify the form; please note that we use a captcha, include the following in your form:

<img src="captcha_code_file.php?rand=<?php echo rand(); 
?>" id='captchaimg' ><br>

Enter the code above here : <input id="captcha" 
name="captcha" type="text"><br>

Input Filtering

To keep the script safe, we sanitize each input key and value using FILTER_SANITIZE_STRING. I strip any HTML code or invalid characters.

Thank you URL

Put your own $thank_you_url in the 2^nd line of the code.

What Does This Script Do?

Check the referrer page and stop the script if it is called directly:

$REFERER = $_SERVER['HTTP_REFERER'];
if(!preg_match("@^http:\/\/(www\.)?$domain\/@",$REFERER)){
                die("This page can't be call directly");
}

Validate user email and user name to prevent injecting the wrong command in the header parameter of the mail() function:

if(!$from_email) $from_email = "web_page@$domain";
if (!filter_var($from_email, FILTER_VALIDATE_EMAIL)) {
                $Err .= 'Invalid email format<br>';
                $from_email = "web_page@$domain";
}

Validate the subject and encode it if needed to prevent send failure:

if ($subject && !preg_match('/^[A-Za-z ]+$/',$subject)){
                $subject = "=?UTF-8?B?".base64_encode($subject)."?=";
}

Store the captcha in session and compare it with the variable

Seek all posted variables

foreach ($_POST as $key => $value)
{
    if ( strpos( strtolower( $key ), 'email' ) !== false ) { 
        $value = filter_var( $value, FILTER_SANITIZE_EMAIL ); 
    } else { 
        $value = filter_var( $value, FILTER_SANITIZE_STRING ); 
    } 
    $value = htmlspecialchars( $value ); 
    $key = filter_var( $key, FILTER_SANITIZE_STRING ); 
    $key = htmlspecialchars( $key ); 
    $message_html .= "<h2>$key</h2><p>$value</p>";
}

Send the message in HTML UTF-8 format to be compatible with most languages
Redirect to thank you URL
```
header('Location: '. $thank_you_url);
```

PHP Mailing Technique

There are lots of mailing techniques in PHP; PEAR Mail, PHP Mailer, and a mail function. However, we just use the mail function as it is common and simple.

PHP Email Validation

PHP FILTER_SANITIZE_EMAIL Filter

Remove all illegal characters from an email address:

$from_email = filter_var($from_email, FILTER_SANITIZE_EMAIL);

PHP FILTER_VALIDATE_EMAIL Filter

Check if the variable $email is a valid email address:

if (!filter_var($from_email, FILTER_VALIDATE_EMAIL)) {                    
    $Err .= 'Invalid email format<br>';               
    $from_email = "web_page@$domain";
}

Validate Email in PHP using a Regular Expression

$pattern = '/^[\w.-]+@[\w.-]+\.[A-Za-z]{2,6}$/';
if(!preg_match($pattern, $from_email)){ 
    $Err .= 'Invalid email format<br>';               
    $from_email = "web_page@$domain";
}

History

14^th October, 2016: Initial version
7^th May, 2021: Article updated

PHP Contact Us Script, Runs Without Modification