Validate Multiple Emails Comma Separated with javascript

Question

I want to validate a string which can be an email or multiple emails separated by commas.

For example:

bill.gates@hotmail.com -> TRUE
bill -> FALSE

Answer 1

You shouldn't match top-level domains with [A-Z]{2,4}:

What about .museum or .travel? What about IDNA domains like .xn--0zwm56d or .xn--11b5bs3a9aj6g?

Also, it's perfectly valid to have an email-address like "John Doe"@example.org.

In my opinion, all you should check on the client side is if the address contains an @ and if there's at least one . after it. On the server side, you could check if the server exists (you might even want to try connecting to the appropriate SMTP port) or just send out a validation mail.

Everything else is prone to errors as the actual regex to check for valid email addresses looks like this.

---

Also, this

return (regex.test(field)) ? true : false;

is a serious WTF - test() already returns a boolean value!

---

If you want to allow different separators, use a regular expression instead of a string for splitting, eg

value.split(/,|;/)

Answer 2

used this for php preg_match_all()

$pattern = '/([\w+\._%-]+@[\w+\.-]+\.[\w+]{2,4}[^,;\s])/';
$text = 'abc@efg.com, efg, hij@emg.com, ak@efg asfbd@efg.com ab@sdfs.com abc+efg@pqr.com';
preg_match_all($pattern, $text, $match);
var_dump($match);

array(2) {
  [0] =>
  array(5) {
    [0] =>
    string(11) "abc@efg.com"
    [1] =>
    string(11) "hij@emg.com"
    [2] =>
    string(13) "asfbd@efg.com"
    [3] =>
    string(11) "ab@sdfs.com"
    [4] =>
    string(15) "abc+efg@pqr.com"
  }
  [1] =>
  array(5) {
    [0] =>
    string(11) "abc@efg.com"
    [1] =>
    string(11) "hij@emg.com"
    [2] =>
    string(13) "asfbd@efg.com"
    [3] =>
    string(11) "ab@sdfs.com"
    [4] =>
    string(15) "abc+efg@pqr.com"
  }
}

Answer 3

How about splitting the string into an array and looping through it passing just one e-mail address at a time?

Answer 4

try this

     function validateEmails(string) {
        var regex = /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/;
        var result = string.replace(/\s/g, "").split(/,|;/);        
        for(var i = 0;i < result.length;i++) {
            if(!regex.test(result[i])) {
                return false;
            }
        }       
        return true;
    }

accepts both comma and semicolon as separator, change that if you want only comma as separator

Answer 5

I would throw an $.trim(result[i]) into that validateMultipleEmailsCommaSeparated function as many people will add the space after their comma.

Of course that is a jQuery thing so do the equivalent your way.

Answer 6

Regex:

((\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*)*([,])*)*