Server Side Form Validation using Regular Expressions

Some days back I had posted " Perfect Javascript Form Validation using RegularExpressions ", one of the reader commented like this "If I disable Javascript?". So in this post I given a simple example about "Server Side Form Validation using Regular Expressions ". Take a look at live demo.

 Download Script     Live Demo


validation.php
Contains PHP code. eregi — Case insensitive regular expression match.

<?php

if($_POST)
{
$name = $_POST['name'];
$email = $_POST['email'];
$username = $_POST['username'];
$password = $_POST['password'];
$gender = $_POST['gender'];

// Full Name

if (eregi('^[A-Za-z0-9 ]{3,20}$',$name))
{
$valid_name=$name;
}
else
{
$error_name='Enter valid Name.';
}

// Email

if (eregi('^[a-zA-Z0-9._-]+@[a-zA-Z0-9._-]+\.([a-zA-Z]{2,4})$', $email))
{
$valid_email=$email;
}
else
{
$error_email='Enter valid Email.';
}

// Usename min 2 char max 20 char

if (eregi('^[A-Za-z0-9_]{3,20}$',$username))
{
$valid_username=$username;
}
else
{
$error_username='Enter valid Username min 3 Chars.';
}

// Password min 6 char max 20 char

if (eregi('^[A-Za-z0-9!@#$%^&*()_]{6,20}$',$password))
{
$valid_password=$password;
}
else
{
$error_password='Enter valid Password min 6 Chars.';
}

// Gender

if ($gender==0)
{
$error_gender='Select Gender';
}
else
{
$valid_gender=$gender;
}

if((strlen($valid_name)>0)&&(strlen($valid_email)>0)
&&(strlen($valid_username)>0)&&(strlen($valid_password)>0) &&$valid_gender>0 )
{
mysql_query(" SQL insert statement ");
header("Location: thanks.html");
}
else{ }

}

?>

index.php
Contains HTML code. You have to include validation.php file.

<php include("validation.php"); ?>
<form method="post" action="" name="form">
Full name : <input type="text" name="name" value="<?php echo$valid_name; ?>" />
<?php echo $error_name; ?>
Email : <input type="text" name="name" value="<?php echo$valid_email; ?>" />
<?php echo $error_email; ?>
Username : <input type="text" name="name" value="<?php echo$valid_username; ?>" />
<?php echo $error_username; ?>
Password : <input type="password" name="name" value="<?php echo$valid_password; ?>" />
<?php echo $error_password; ?>
Gender : <select name="gender">
<option value="0">Gender</option>
<option value="1">Male</option>
<option value="2">Female</option>
</select>
<?php echo $error_gender; ?>
</form>