Advertisement
Online Test Banks
Score higher
See Online Test Banks
eLearning
Learning anything is easy
Browse Online Courses
Mobile Apps
Learning on the go
Explore Mobile Apps
Dummies Store
Shop for books and more
Start Shopping

How to Validate URLs and E-Mail Addresses in Web Form Fields

Truly validating an e-mail address in a web form field is a surprisingly difficult task. The standard for e-mail addresses allows for complex combinations of letters, numbers, and special characters, some of which can only appear in certain positions. PHP versions 5.2 and greater include a filter_var() function that takes this complexity away and makes it easier to filter things like e-mail addresses and URLs (among other things).

Validate an e-mail address

The filter_var() function includes a number of built-in tests to check to see if an e-mail address is valid.

Select Validation Filters in PHP
Filter Description
FILTER_VALIDATE_BOOLEAN Validates that a value is a Boolean.
FILTER_VALIDATE_INT Validates that a number is an integer.
FILTER_VALIDATE_FLOAT Validates that a number is a floating point number.
FILTER_VALIDATE_IP Validates an IP address.
FILTER_VALIDATE_EMAIL Validates an e-mail address.
FILTER_VALIDATE_URL Validates a URL.

Using the filters is very easy. For example, here's the code to validate an e-mail address. This code could be plugged into the form-process.php file above the final disposition section:

if (!filter_var($_POST['email'],FILTER_VALIDATE_EMAIL)) {
    $_SESSION['error'][] = "Invalid e-mail address";
}

That code is all you need to validate an e-mail address in PHP.

Validate a URL

URLs can be validated in the same way. Say you have a variable called $url. The validation code looks the same; it just uses a different filter.

if (!filter_var($url,FILTER_VALIDATE_URL)) {
    $_SESSION['error'][] = "Invalid URL";
}
  • Add a Comment
  • Print
  • Share
blog comments powered by Disqus
Advertisement
Advertisement

Inside Dummies.com

Dummies.com Sweepstakes

Win an iPad Mini. Enter to win now!