Web Dev> Validate Password creation with PHP

The following can be used to test for different criteria in passwords.

<?php
$min = 6;
$max = 20;
$password = $_POST['password'];
$confirmpw = $_POST['confirmpw'];
if($password != $confirmpw){
$error .= "Password and Confirm password do not match! <br />";
}
if( strlen($password) < $min ) {
$error .= "Password too short! <br />";
}
if( strlen($password) > $max ) {
$error .= "Password too long! <br />";
}
if( !preg_match("#[0-9]+#", $password) ) {
$error .= "Password must include at least one number! <br />";
}
if( !preg_match("#[a-z]+#", $password) ) {
$error .= "Password must include at least one letter! <br />";
}
if( !preg_match("#[A-Z]+#", $password) ) {
$error .= "Password must include at least one CAPITAL! <br />";
}
if( !preg_match("#\W+#", $password) ) {
$error .= "Password must include at least one symbol! <br />";
}
if($error){
echo "Password Failure: $error";
} else {
// Code to execute on success.
}
?>