RegExp - Validate E-mail

[Rick Bull]

I know virtually no Regular Expressions, and I want to know if this about right for validating a given e-mail address?

var emailRE = new RegExp(/^(\S)+\@(\S)+\.(\S)+$/);
alert(emailRE.test(formElement.email.value))

[jeffmott]

The best you're going to get.

var emailRE = new RegExp(/^[^()<>@,;:\\".[\]\x00-\x20\x7f-\xff]+(?:\.[^()<>@,;:\\".[\]\x00-\x20\x7f-\xff]+)*\@[^()<>@,;:\\".[\]\x00-\x20\x7f-\xff]+(?:\.[^()<>@,;:\\".[\]\x00-\x20\x7f-\xff]+)*$/);
alert(emailRE.test(formElement.email.value))

This regular expression was derived from [RFC822] Standard for ARPA Internet Text Messages, Address Specification (http://www.w3.org/Protocols/rfc822/#z8)

[jeffmott]

I was curious if anyone knew if RFC822 is outdated and been replaced by another recommendation. One of my concerns with it is the domain is allowed to contain symbol characters.

[jeffmott]

Here's a possible alterative. With an address of the form local-part "@" domain, [RFC822] (http://www.w3.org/Protocols/rfc822/#z8) was used for the local-part and [RFC2396]Uniform Resource Identifiers (URI): Generic Syntax (http://www.ietf.org/rfc/rfc2396.txt) for the domain.

var emailRE = new RegExp(/^[^()<>@,;:\\".[\]\x00-\x20\x7f-\xff]+(?:\.[^()<>@,;:\\".[\]\x00-\x20\x7f-\xff]+)*\@(?:(?:[a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9]\.)*(?:[a-zA-Z]|[a-zA-Z][a-zA-Z0-9\-]*[a-zA-Z0-9])\.?|[0-9]+.[0-9]+.[0-9]+.[0-9]+)(?::[0-9]*)?$/);

...though I've never known the local-part to contain symbols either (!#$%^&*{}'?/) grrr
Which document specifically and accurately describes the allowed syntax of an e-mail address?

[Rick Bull]

Thanks for the input guys.

I'm not sure about what characters an e-mail can contain Jeff, maybe I'll see if I can find something online somewhere.