PHP form that collects email and website address

Question

I have built the following form that collects both email addresses and website urls from people. In the database the email and website url are set to be unique so a person cannot enter the same email and website twice.

However being new to PHP I want to double check that the form does not contain any serious problems that could allow a person to do something malicious with the form and/or has validation issues that could be exploited. Also because I want to hide the form on postback BUT show it again for errors, I have ended up duplicating the form which isn't ideal but not a big deal in this circumstance as it's just a quick form. The main factor is making sure the validation is pretty strong and no holes exist in terms of server/sql attacks in the form.

<?php

if($_SERVER['REQUEST_METHOD'] == 'POST')
{
    // DATABASE CONNECTION HERE

    $email = mysql_real_escape_string($_POST['EMAIL']);
    $website = mysql_real_escape_string($_POST['WEBSITE']);

    if ( $email == '' || $website == '' || !filter_var($website, FILTER_VALIDATE_URL) || !filter_var($email, FILTER_VALIDATE_EMAIL) )
    {
        echo '<p style="color:red;">You must fill out all fields correctly and duplicate emails/websites are not permitted!</p>';

    ?>
        <form action="./" method="post">

            <label for="EMAIL">Email Address</label>
            <input type="email" value="" name="EMAIL" id="EMAIL" required>
            <label for="WEBSITE">Website URL</label>
            <input type="url" value="" name="WEBSITE" id="WEBSITE" required>
            <input type="submit" value="Join" name="join">

        </form>

    <?php

    }
    else
    {
        $query = "INSERT INTO list VALUES (NULL, '$email','$website')";

        $result = mysql_query($query);
        echo '<p>THANKS!</p>';
    }
}
else
{

?>

<form action="./" method="post">

    <label for="EMAIL">Email Address</label>
    <input type="email" value="" name="EMAIL" id="EMAIL" required>
    <label for="WEBSITE">Website URL</label>
    <input type="url" value="" name="WEBSITE" id="WEBSITE" required>
    <input type="submit" value="Subscribe" name="subscribe">

</form>

<?php } ?>

Answer 1

You could validate the values using these validation filters . You can find some instructions for this here .

To prevent cross site scripting and similar attack vectors you should not insert the email or url into the database unless it has been validated.

Answer 2

I think it should work great as long as you are using the important functions such as real escape and validate url nd email. keep it up

Thnx