Is email field assistance still necessary?

Question

For registration forms, it seems the trend now is to allow any password a user wants, as long as you inform him if it's weak.

With this in mind, should we still validate email fields on the client side, or do we assume that people by now have learned to type in their own email address without side wheels and a cheerleading squad?

Specifically,

1. Does anyone have data on how often people actually make mistakes in typing in their own email address in an input field?

2. Should one wish validation, is JavaScript the best option at the moment, or can CSS type="email" required provide a good user experience? (For instance, how do you tell the browser not to error-style the input field until the user has typed at least one character?)

(Security-checking should still be done on the server-side. When I am asking about here is user assistance.)

Answer 1

Don't "validate" on the client side. Email validation is actually a difficult problem and an enormous number of sites claim my email address is invalid. These sites also prevent my (perfectly valid) email address from being used. Getting it wrong can be detrimental, getting it right is tough.

On the client side, you can parse the email address to be helpful, but I recommend against preventing the user from proceeding. Instead, use the email system to validate the email. Send an email to the account with a link that "verifies" the address. This is the most accurate way to validate an email address and has the added benefit of preventing one person using another person's email address in registration.

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It may be usefult to read this post:

http://haacked.com/archive/2007/08/21/i-knew-how-to-validate-an-email-address-until-i.aspx

Answer 2

Yes it's still very necessary. Email validation isn't just about people learning the email pattern, it's also for your own app's security, to prevent mindless inputs or potentially malicious inputs.

Answer 3

Yes, it would be very wise to include email validation.

1. About 1 out of 15 emails are invalid (by invalid I mean not in email format, to distinguish from valid emails that bounce back upon reply; see below for more).
2. Do javascript inline validation on blur.

Due to technology constraints, one of my sites has a contact form with no email validation (and no email retype field). About 1 out of 15 emails are invalid - with people sometimes putting all sorts of garbage in (in all cases the message itself is from a real person - no spam). It's a site for music-technology enthusiastics, so most users should be fairly computer literate.