checking if data entered alphanumeric

[Anon]

Hi,

I'm using PHP and MySQL. I have an HTML-page where there are several input fields. There is one field that is supposed to contain a SERIAL NUMBER (numeric data). I want to check if the user has entered alphanumeric data, because the insertion is succesful, however the value is changed to 0 by MySQL. Can you give me which function to use or what is the general idea? An example would be greatly appreciated.

Thanks, Akos

[Anon]

if it is truely numeric (only numbers 0 through9, NOTHIN else) you can check it with is_numeric($string)

[Anon]

Ok, ereg is your friend in this case 🙂

Try the following (with $value containing the value you want checked)

if (ereg("^{([A-Za-z0-9]*)$",} $value)
// This is alphanumeric
else
// sorry, its not

Hope that helps!

Chris King

[Anon]

Not really: the data you get from the POST or GET is in string form.

Check this out:

   <?php
   
   $data_from_POST = "1234";
   
   echo gettype( $data_from_POST );
   
   ?>
   

and see what it tells you. Chris's suggestion is the way to go!

[Anon]

Sure, but now try this:

$data_from_POST = "1234";
echo gettype( $data_from_POST );
echo "\n";
if (is_numeric($data_from_POST))
{
echo "is numeric\n";
}
else
{
echo "is not numeric\n";
};

then try changing the "1234" to "a1234"