Simple Email validation regular Expression for Javascript

Following regular expression will validate emails.  

var re =/^[A-Z0-9a-z\._+]+@[A-Za-z0-9\.-]+\.([A-Za-z]{2,4})$/;

re.test(value);

We will discuss above regular expression part by part.

Examples - 

part1@part2.part3

1. abcd+ef@bbb.com

2. cccc_efg@bbb.lk

3. cccc.efg@bbb.net

^ ==> Start of the expression

Part1

[A-Z0-9a-z\._+]+  ==> There can be many of  A-Z upper case characters, a-z lower case characters, 0-9 numbers, dots and plus signs.

@ ==> There must be @ sign after first part of the email

Part2

[A-Za-z0-9\.-]+ ==> After @ sign there can be same kind of character sets as part 1 (part 2 of email)

\. ==> There must be dot character before 3rd part of the email. It should be properly escaped. That is why we use backslash (\)

Part3

([A-Za-z]{2,4}) ==> There are must be two to four characters({2,4})including  A-Z upper case characters or a-z lower case characters.  Curly brackets specify the range of characters. So, 2 is minimum number of characters and 4 is maximum number of characters

Regular Expression (Regex) javascript test() Method

This test() method of javacription is used test for match in a string such as emails. If there is a match found it returns true otherwise false.

re.test(value);

value variable in test() method is the value that comes to function to validate such as email or any other string

Enjoy