PHP Manual string functions site: http://www.php.net/manual/en/ref.strings.php
empty($str)
strlen($str)
substr($str, $i[, $len])
<?php if (empty($first_name)) { $message = 'You must enter the first name.'; } ?>
<?php $name = 'Ray Harris'; $length = strlen($name); // $length is 10 $first_name = substr($name, 0, 3); // $first_name is 'Ray' $last_name = substr($name, 4); // $last_name is 'Harris' $last_name = substr($name, -6); // $last_name is 'Harris' ?>