How to add php code to join field

What is the expected code I can add to the CHECK field in profile fields?

I've attached the screen shoot of the screen...

Should I write a php expression or what?

For example in City....I want to check if it's eq to "New York" or "Chicago" and if not not to allow entering other cities..

Thanks

Try this in the City, Advanced,  Check field;

return strtolower($arg0) == 'new york' || ($arg0) == 'chicago';

Let me know if that works for you.

Thank you very much! It works...

How come that after I've added check to a specific field in the JOIN form people are still able (spammer) to aviod this check?

How all those spammer are able to join the site? it must be something I miss in the security ?

Please help

http://www.boonex.com/forums/?action=goto&my_threads=1#topic/Clean-and-Tweak-My-Site-.htm

 Almost all the spammers that used to join my site always put "New York" as their city. I think it's the only city in the US they know. If you're going to check something you might want to check another field.

Skyforum,

I read your posting and I like it. I'll give it a try.

can I use it on the city field? instead of email field, replace email with city?

I think it's better to create a table with that list and read it directly from there. With deano mood we can add through the admin and no need to open the file and edit that.

Thanks and I'll try it too.

Just wondering how they could add them self even if I have a check on city and Dolphin code is not blocking them. They must know a hole in the code.