Re: [PHP] How can I check for characters in a $_POST[] variable?

[Tommy Pham]

On Thu, Sep 22, 2011 at 7:55 AM, Eric <eric_justin_al...@cfl.rr.com> wrote:

> I have this problem when using php because my computer recognizes
> the characters "." and ".." as an existing file when I use file_exists.
> Also
> I want to check $_POST["username"] for characters other then A-Z a-z and
> 0-9.
> If it contains anything other then, I would like to prompt the user but
> I can't seam to use foreach properly and I don't know how to itterate
> through the post variable with a for loop while loop or do while loop.


$pattern = '/^[A-Za-z0-9]/';
/* http://php.net/control-structures.foreach */
foreach ($_POST as $key => $value)
{
/* http://php.net/function.preg-match */
  if (preg_match($pattern, $value) > 0)
  {
      /* prompt user */
  }
}