javascript - Regex: Email validation that allows only hyphens in the middle of the domain and top-level domain

I know this is been asked tons of times before , but I haven't found anything that really meets all the conditions that an email address must meet to be considered valid.

Considering the following as the structure of an email address :

part1@part2.part3.part4

• part1=username




• part2=domain




• part3 and part4 =top-level domain

These are all the conditions that must be met:

1. An email address must not accept white spaces


2. An email address must not end in a dot or a character other than a letter or a number


3. Only one @ sign is allowed


4. There can not be a special character before or after the at sign


5. There can not be a special character before or after the domain dot (the dot after part2 of the email address)


6. You can not enter two or more dots in a row in the username



7. In the domain , between @ and the dot, the characters that are next to the @ and the dot must be a letter or number, in the middle the only special character allowed is the hyphen.


8. The same in step 7 goes for the top-level domain(part 3 and part 4 or the email)

This is the regular expression I currently using :

^([\w\.\-]+)@([\w\-]+)((\.(\w){2,9})+)$

But it does not meet conditions :4,5,6,7 and 8

I'm just trying to figure out how to complement my regular expression and learn in the process.

The only special characters allowed in the email address are : dots, hyphens,underscores and the at sign

Here's a list of invalid emails

mkyong – must contains “@” symbol

mkyong123@.com – domain can not start with dot “.”

mkyong()*@gmail.com – email’s is only allow character, digit, underscore and dash

mkyong@%*.com – email’s tld is only allow character and digit

mkyong..2002@gmail.com – double dots “.” are not allow

mkyong.@gmail.com – email’s last character can not end with dot “.”

mkyong@mkyong@gmail.com – double “@” is not allow

mkyong@gmail.com.1a -email’s tld which has two characters can not contains digit

Valid:

mkyong@yahoo.com

mkyong-100@yahoo.com

mkyong.100@yahoo.com

mkyong111@mkyong.com

mkyong-100@mkyong.net

mkyong.100@mkyong.com.au

mkyong@1.com

mkyong@gmail.com.com

mkyong-100@yahoo-test.com

Answer

This is the best I have been able to do as per your list of valid and invalid email addresses:

^([\w-]|(?

DEMO

Updated:

^([\w-]|(?