How can I apply this code for email validation to JavaScript?

Question

How can I apply this code to JavaScript?

This code will check email address validation in PHP. But i want to apply this code to JavaScript.

How can I do that?

PHP

<?php
    $strEmail = $_POST[email_send_value];
    if (!eregi("^[_a-z0-9-]+(\.[_a-z0-9-]+)*@[a-z0-9-]+(\.[a-z0-9-]+)*(\.[a-z]{2,3})$", $strEmail))
    {
        // NOT OK //
    }
    else
    {
        // OK //
    }
?>

JavaScript

<script>
    var email_var = document.getElementById("CheckEmail").value;
    .
    .
    .
    .
    .
</script>

Answer 1

function validateEmail(email) { 
    var re = /^(([^<>()[\]\\.,;:\s@\"]+(\.[^<>()[\]\\.,;:\s@\"]+)*)|(\".+\"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/;
    return re.test(email);
} 

Validate email address in JavaScript?