Validating Email Addresses

The following script verifies that an email address mostly follows the rules outlined in RFC 2822. This won't prevent someone from entering a false (but RFCcompliant) email address such as dontbugmeman@nonexistentdomain.com, but it will catch some typos.

<?php
function is_email($email) {
 if (! preg_match( '/^[A-Za-z0-9!#$%&\'*+-/=?^_`{|}~]+@[A-Za-z0-9-]+(\.[AZa-z0-9-]+)+[A-Za-z]$/', $email)) {
            return false;
 } 
 else {
  return true;
 }
}
?>

This script uses regular expression to check whether the given email uses proper email characters (alphabetical, dots, dashes, slashes, and so on), an @ sign in the middle, and at least one dot-something on the end.

Hope it helps.

Protecting Email Addresses from Spam Collectors

Many spammers today use harvesting software that scours websites looking for email addresses on web pages. Once found, spammers start sending spam to these addresses. It is therefore beneficial to find some way to block them from doing this. Many techniques on how to do this are described on the Webfrom basic methods such as adding the text "NOSPAM" into your email and hoping that human beings understand to remove it, to much more complex methods.

A standard tactic that we will explore here is to use JavaScript. Because most crawlers are not going to bother to execute any JavaScript on the page before trying to look for email addresses, this gives us a tool. We can print the link via JavaScript so that it isn't truly part of the page. This isn't enough though because the email address would still be visible in the JavaScript code.

The solution therefore is to convert the entire link into ASCII codes, save them in a JavaScript array, and then use JavaScript to turn it back into regular HTML. The only way that a script scanning the page would ever figure this out is if it does have a JavaScript engine in it and executes the page.

The following code is a PHP function that generates the JavaScript automatically, making it easy to use.

<?php
// A function that will protect email addreses, by generating JavaScript,
//  which will in turn generate the Email Link!
function write_protected_email($address) {
    $link = "<a href=\"mailto:{$address}\">{$address}</a>";
    $codes = array();
    for ($i = 0; $i < strlen($link); $i++) {
        $codes[] = ord($link{$i});
    }
    $outputarray = implode(',', $codes);

    echo "
<script>
var datapoints = new Array({$outputarray});
for (var i = 0; i < datapoints.length; i++)
  { document.write(String.fromCharCode(datapoints[i])); }
</script>
";
}

// Test this to see if it works:
write_protected_email('Francesca_Angelo@example.com');
?>

Hope it helps.