how to validate email with regular expression code example

Example 1: email regex

//Author: Mohammad Arman Khan
//Regular Expresssion for e-mail validation
var email_validator_regex = /^[a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-]+@[a-zA-Z0-9-]+(?:\.[a-zA-Z0-9-]+)*$/;

Example 2: regex pattern to validate email

[a-zA-Z0-9._-]{3,}@[a-zA-Z0-9.-]{3,}\.[a-zA-Z]{2,4}