Email format validation in Php using regular expressions

Related concepts: HTML forms · PHP form validation

Validate an email address

For normal server-side email-format validation, FILTER_VALIDATE_EMAIL is clearer and more maintainable than a custom regular expression. Format validation does not prove that the mailbox exists.

$email = trim($_POST['email'] ?? '');

if (filter_var($email, FILTER_VALIDATE_EMAIL) !== false) {
    echo 'Valid email format';
} else {
    echo 'Invalid email format';
}

We check the address format only; this does not prove the mailbox exists.

In an input field we can verify whether an email address has a valid format using PHP's built-in filter API. This is a part of php form validation we do for other entries to check proper formatted data is entered by the user or not.

Please not that we are not checking the validation or existence of the URL or the service provider. We are only checking / validating the format of the email address.

This code can be used as a part of the other entered data validation used. You can read the php form validation here.

The HTML FORM for user to input email

<form method=post action=''>Enter any email address 
<input type=text name=email value=$email>
<input type=submit value=Check>
<input type=hidden value=test name=todo>
</form>

How to receive email address

Visitors enter their email address in a textbox kept inside a web form.
From a web form we will get email address either by GET or POST method to the processing script. For ready reference here are two ways to get the email address from a web form.

$email=$_GET['email']; // GET method 
$email=$_POST['email']; // POST method

Using FILTER_VALIDATE_EMAIL

Use filter_var($email, FILTER_VALIDATE_EMAIL) for normal server-side email-format validation instead of maintaining a custom regular expression.

PHP's filter extension provides built-in validators for common input types, including email addresses.
FILTER_VALIDATE_EMAIL Email validation using Ajax & PHP
PHP Form

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

About the author Watch on YouTube

Connect:

Subscribe to our YouTube Channel here

albusaidy	16-11-2014
worked great for me.. I love the fact that the page I was working on stayed on screen, and script showed where change needed to be made. Awesome Is there a way to make sure people do not enter www. in front of their email, it happens often.

John S	17-04-2019
Hello, eregi() is deprecated as of PHP 5.3 Thanks.

good	22-05-2013
its interestiing..!!

Email validation within a form in PHP

Validate an email address

The HTML FORM for user to input email

How to receive email address

Using FILTER_VALIDATE_EMAIL

Subhendu Mohapatra