Js email validation

Here are some examples of JavaScript email validation:

Simple Email Validation

function validateEmail(email) {
  var re = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
  return re.test(email);
}

This regular expression matches most common email formats, but it's not foolproof. It allows for letters, numbers, dot (.), hyphen (-), underscore (_), and plus sign (+) in the local part, and requires a top-level domain (TLD) with at least 2 characters.

More Advanced Email Validation

function validateEmail(email) {
  var re = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
  var localPart = email.substring(0, email.indexOf('@'));
  var domain = email.substring(email.indexOf('@') + 1);
  if (localPart.length > 64) return false;
  if (domain.length > 253) return false;
  if (!re.test(email)) return false;
  return true;
}

This version of the function also checks the length of the local part and domain, which are limited by the RFC 5322 standard.

Using a Library

const emailValidator = require('email-validator');

function validateEmail(email) {
  return emailValidator.validate(email);
}

This uses the email-validator library, which provides a more comprehensive and accurate email validation.

Example Usage

var email = '[email protected]';
if (validateEmail(email)) {
  console.log('Email is valid');
} else {
  console.log('Email is not valid');
}

Note that email validation is not foolproof, and it's always a good idea to use a combination of validation and other security measures to ensure the security of your application.