Help pls validating input box.How?

[bladez]

i have a form for login n password

i want to validate on server site to check if the content are either characters or numbers only ...

 

Example :

 

Username : bladez                    - accecpted

Username : bladez99                - accecpted

Username : *>dsa*dad            - Rejected

Username : <?php bla ?>        - rejected

 

Which means if it doesnt meet those pattents its an error ..how do i do that in PHP?

[hackerkts]

You can try regex a-zA-Z0-9

[colombian]

To validate particular patterns, you'll need to venture into regular expressions.

 

Here is a helpful tutorial:

http://weblogtoolscollection.com/regex/regex.php

 

Or just go to:

http://us3.php.net/regex

 

 

The number portion of it you can check with the is_numeric function.

So

<?php if (!is_numeric($POST['variable'])) {
// Errors here
} ?>

 

 

[AdRock]

You can do this

 

if(!ereg("^[A-Za-z0-9 \-]{4,30}$",$username))

 

The bit that does [A-Za-z0-9] will allow numbers and letters only

 

 

The bit that does {4,30} allows between 4 and 30 letters/numbers and $ username is the input box name