On Tue, 2003-01-07 at 03:20, Steve Watt wrote: > In article <[EMAIL PROTECTED]> you >write: > [ snip ] > >SOLUTION : > >========== > [ snip ] > > if(!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", > >$email) && $email != > >"") { > > Please note that there are many more characters valid in the LHS of an > email address, for example +, that are often desirable. Disallowing > such addresses is a major nuisance.
Indeed. In fact, ANY ASCII character can appear in the local-part of the address, because the local part can be a quoted-string and a quoted-string can contain any virtually any ASCII. Then, the domain can be a domain-literal, and this can contain CFWS, which can contain comments. Comments cannot be recognised by a regular expression as comments nest. RFC 2822 address validation requires knowlege of that standard. David Wilson Isode Limited
