special characters

[salim]

Hi

can anybody help me solve this problem.

I need to check my text box for valid alplabets.
that is a-z,A-Z,0-9.

if any other character entered in the box it should reject.

I need the preg_match code for this,tried a lot but nothing is working

thnx

[artemis]

Something like..

if(preg_match("/[^a-z0-9]/i",$string)){
echo 'Non-alphanumeric characters found';
}

[salim]

yeh fine

preg_match('/[^a-zA-Z0-9]/',$_REQUEST['url'])

this s the code i am using

Thanks for the help

[artemis]

A quick tip, you have done:

preg_match('/[^a-zA-Z0-9]/',$_REQUEST['url'])

Which is fine, except there is no need for the a-zA-Z.
If you look at my version you will see there is the 'i' flag at the end:

preg_match('/[^a-z0-9]/i',$_REQUEST['url'])

Which means it does a case-insensitive search so it will match the upper case characters as well

[salim]

yep i understood it.

But i just posted my code.(just like that).

Once again i thank you for the help

[NogDog]

A bit faster will be:

if(!ctype_alnum($_REQUEST['url']))
{
// invalid input
}