ereg stuff

[vcphp]

hi guys,

 

I'm try validating one email input, like $email = "[email protected]"; and i make that, but i see one code in the web, i i don't understand one thing.

 

what the difference between:

 

$exp =  "^[a-z0-9_\.\-]+@[a-z0-9_\.\-]+\.[a-z]{2,4}$";

 

and

 

$exp2 = "^[a-z0-9_\.\-]+@[a-z0-9_\.\-]*[a-z0-9_\-]+\.[a-z]{2,4}$";

 

 

Here is the code that i can't understand *[a-z0-9_\-]

 

Tks 

 

 

[Psycho]

That allows for an email addres with 1 or more sub-domains.

 

The part before the asterisk (which is common to both expressions) allows for an alpha-numeric (plus '_' & '-') ending in a period. The asterisk means it can match the preceeding section 0 or multiple times.

 

However, both expressions are wrong because of several reasons:

- They do not allow upper case characters

- They would allow the domain to begin with a period or have two periods in succession

- They do not allow the plus sign ('+') in the username portion, which is a perfectly acceptable character in an email address

 

 

Here is a long, but very comprehensive, regex expression for email addresses:

 

^([a-zA-Z0-9-_\+])+([\.]?[a-zA-Z0-9-_\+])*@([a-zA-Z0-9])+([\.-]?[a-zA-Z0-9])*\.([a-zA-Z]{2,})$