php username validations

[Nandini]

Hi

i am designing php aurthentication script. I want to validate username field while create useraccount. I want to validate username as same as gmail username.

 

That means

 

only letters (a-z), numbers (0-9), and periods (.) are allowed. and

 

username cannot contain consecutive periods (.),  like this.

 

i have used the following line of code. But i did not get complete solution.

 

eif(!eregi("^[a-z0-9.]{4,16}$",$_POST['username']))

{

$errmsg='Only letters (a-z), numbers (0-9), and periods (.) are allowed for username.';

}

 

Can anyone give me solution

[gevans]

You need to escape the '.' character, so try the following;

 

eregi("^[a-z0-9\.]{4,16}$",$_POST['username'])