Darren Provine at Rowan University

Web-Programming Specific Links

This is a set of links likely to be interesting to web programming students. Also see my regular link page.

Web Users Judge Sites in the Blink of an Eye

A study indicates that users evaluate a site immediately upon first seeing it, and that their first impression affects how much time they spend reading a site.

Perl Expression For Matching RFC822 Addresses

This link gives a regular expression in Perl for checking whether an email address is valid. You can see the official docs for email addresses at: http://www.faqs.org/rfcs/rfc2822.html . (RFC2822 updated RFC822, but the address syntax requirements didn't change.) The short version is that the local part of an email address (the bit to the left of the @ sign) is either a "dot-atom", or a "quoted-string". If it's a dot-atom, then all of the following characters are legal:

   !#$%&'*+-/=?^_`{|}~.0123456789abcdefghijklmnlopqrstuvwxyzABCDEFGHIJKLMNLOPQRSTUVWXYZ
      

So, for example, "*@*.*" is a perfectly legal email address.

It's shorter to list the characters that are illegal:

      ()<>[]:;@\,"
      

and control characters.

If you make the address a "quoted-string", then you can include all printable characters and most control characters. A "quoted-string" can contain any seven-bit character other than NUL, TAB, CR and LF.

So, if you're trying to verify that an address is legal, use Perl's Mail::Address, instead of doing it yourself.