need to restricting forms submits based on data

[ChrisVersion2]

I have a form located here https://www.lgw.com/dev/sampleformcard.htm

and I'd like to stop people from submitting the form if there credit card starts with several different combination of 4 numbers.

The list is very long (almost 300 different combo) and I was looking for suggestions on how I could accomplish this.

My first thought was it break up the one field into 4 fields, (like the four groups of numbers on your credit card) and just run the filter on the first field.

what programming language would I use? maybe PHP and run it against a CSV file?

Any direction would be helpful.


Regards,
Chris

[Jas]

PHP would do great, and you would not have to break it up into four feilds-- just use the preg_split functions to grab the first four numbers. You could also store the numbers in a MySQL database and retrive them that way, as opposed to the CSV, but whatever way you like.

[ChrisVersion2]

I have no experience in mySQL, but PHP might be the way to go, any chance you could show a sample, and/or point me to a sample?


thanks

[Jas]

I threw this together really quick, but hopefully it works.

<?php

//check to see if the form has been set
if(isset($_POST['submit'])){
    #CONNECT TO MYSQL HERE
    //get first 4 numbers
    $credit = preg_split("/[\D{5}]/",$_POST['number']);
    //look in mysql for the numbers
    $rows = MySQL_query("SELECT * FROM table WHERE number = \"".$credit[0]."\"");
    //see if there was at least one match
    if(MySQL_num_rows($rows) <= 1){\
        die('FOUND A MATCH FOR THE CREDIT CARD NUMBER');
    }else{
        //process the info
    }
    
}else{
    echo "<form action='".$_SERVER['PHP_SELF']."' method='POST'>
    <input type='text' name='number'>
    <input type='submit' name='submit' value='submit'>    
</form>";
}

?>