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

On Thu 22 Sep 2011 08:25:29 PM IST, Eric 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. file_exists() for . and .. would always return true, because they really exist! . is an alias for the current directory and .. for the parent directory. This is irrespective of OS. To search $_POST["username"] for characters other than A-Z, a-z, 0-9, you can use preg_match something like this (there's an alpha class as well, but I'm not sure about it): if(preg_match('(.*)^[A-Za-z0-9]+', $_POST['username']) !== 0) { // string contains other characters, write the code } -- Nilesh Govindarajan http://nileshgr.com