Simple email regex, make sure user includes dot domain?

Question

I don't mess around with Regex too much but have been able to get this one online. /.+@.+/. This will return true with both joe@joe and joe@joe.com. I want to make it so a user must supply a domain extension otherwise I want it to fail, I presume this is quite simple but I just can't figure it out. I've tried /.+@.+.\S/ but that didn't work. Any help would be great, thanks!

This will be used in both PHP and javascript. The current one works in both, the new will need to also.

Possible duplicate of [Using a regular expression to validate an email address](http://stackoverflow.com/questions/201323/using-a-regular-expression-to-validate-an-email-address) — cartant, Mar 28 '17 at 04:26
From http://www.w3.org/TR/html5/forms.html#valid-e-mail-address `^[a-zA-Z0-9.!#$%&'*+/=?^_\`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$` — , Mar 28 '17 at 04:49

diavolic · Accepted Answer · 2017-03-28T04:33:18.993

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Here is expression

/\w+@\w+\.\w{2,10}/

to allow more characters:

/[\w\-\._]+@[\w\-\._]+\.\w{2,10}/

edited Mar 28 '17 at 04:33

answered Mar 28 '17 at 04:22

diavolic

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Thank you, nice and simple! – Joe Scotto Mar 28 '17 at 04:29
It's no longer incorrect now, but by using the `\w` category, you're excluding a lot of characters that are allowed in an email address. – Robby Cornelissen Mar 28 '17 at 04:29
Is there a way to allow those characters? – Joe Scotto Mar 28 '17 at 04:31
@RobbyCornelissen Elaborate? – Joe Scotto Mar 28 '17 at 04:38
http://www.ietf.org/rfc/rfc5322.txt It's simple: either you go for a correct regex (like the one in the accepted answer of the linked duplicated question), or you choose some trade-off. That trade-off is that you'll end up with a pattern that's either too wide or too narrow. If you're gonna go too wide, you might as well accept anything that is not a space: `\S+@\S+\.\S+` – Robby Cornelissen Mar 28 '17 at 04:40
Even using non-space is too narrow in some cases. `"Joe Blow"@joe.com` is a valid address. – Robby Cornelissen Mar 28 '17 at 04:47

score 1 · Answer 2 · edited Jun 13 '20 at 01:20

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The regex here works for me (from http://www.regextester.com/19 )

/^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?(?:\.[a-zA-Z0-9](?:[a-zA-Z0-9-]{0,61}[a-zA-Z0-9])?)*$/i

As does this example of regex inside JavaScript from plnkr here: http://embed.plnkr.co/ZlbA1I2TsDBUmDb9o0gj/

edited Jun 13 '20 at 01:20

David

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answered Mar 28 '17 at 04:33

ole turvoll

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score 0 · Answer 3 · edited May 23 '17 at 12:10

Given that I don't know what the rest of your code is and you might really need this for both PHP and JavaScript I will suggest a different approach as I don't agree with the solution given in the accepted answer because it will match email addresses like -@-.aa, .@.-.aa, .@_.aa etc.

I'd suggest you use PHP's filter_var with the FILTER_VALIDATE_EMAIL filter which

validates e-mail addresses against the syntax in RFC 822, with the exceptions that comments and whitespace folding and dotless domain names are not supported.

and probably an additional AJAX call from JavaScript .

Regular Expressions matching all valid email address are not trivial at all and I'm not even sure you can rely on them for matching ALL valid email addresses.

For more information please take a look at Validate email address in JavaScript? and Using a regular expression to validate an email address

Mayur Padshala · Answer 4 · 2017-03-28T04:28:29.930

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.+\@.+\.{1}.+

This is a simple regex and will match the required criteria

edited Mar 28 '17 at 04:28

answered Mar 28 '17 at 04:22

Mayur Padshala

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I've used them and it's extremely complex. I'm looking for something quite simple and short. I don't want a 200+ character regex. – Joe Scotto Mar 28 '17 at 04:23
No need to escape the `@` – Robby Cornelissen Mar 28 '17 at 04:32
@Mayur So you say `something @ something . . . com` is a valid email address? – mrun Mar 28 '17 at 06:02

D_S_B · Answer 5 · 2017-03-28T04:31:00.710

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For a simple regex that will accept any domain extension of one character or longer, try: /.+@.+\..+/

For a 2 character domain extension or longer, try: /.+@.+\..{2,}/

edited Mar 28 '17 at 04:31

answered Mar 28 '17 at 04:24

D_S_B

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That still matches on `joe@joe` – Joe Scotto Mar 28 '17 at 04:25
If you test it on this site, you will see that it does not, in fact match that. https://regex101.com/ – D_S_B Mar 28 '17 at 04:26
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That is where I'm testing. `/.+@.+..+/` matches `joe@joe`. – Joe Scotto Mar 28 '17 at 04:28
Oh, I see one of the delimeters got stripped from my copy paste. Let me update my answer. – D_S_B Mar 28 '17 at 04:29

Simple email regex, make sure user includes dot domain?

5 Answers5