Hugh Lashbrooke

“WooCommerce Email Validation” is an extension for WooCommerce that adds a ‘confirm email address’ field to the checkout page as a required field. This will ensure that your customers will enter a correct email address, making managing your orders far easier and more reliable. If a customer’s email address does not match up then they will receive a standard validation error on the checkout page informing them that they need to make sure that their email addresses are the same.
This extension is WooCommerce 3.x compatible and supports localisation using WPML. It has built-in translations for English, German, Spanish, Dutch, Swedish, Japanese, Polish, Brazilian Portuguese, Hungarian and Serbian.
Want to contribute? <a href="https://github.com/hlashbrooke/Woocommerce-Email-Validation" rel="nofollow ugc">Fork the GitHub repository</a>.
<h3>Usage</h3>
Simply upload the plugin and you’re good to go. There are no options to configure – the extension just works.

WooCommerce Email Validation

Adds a 'confirm email address' field to the WooCommerce checkout page.

calliko

Validation Plugin comments. The plugin is based on js-script jquery.validate. 
The plugin does not require any settings and works automatically for standard WordPress comments, of course, if you have a standard theme.

comment validation

Хороший простой плагин, работает из коробки ровно так, как ты и ожидаешь. 

Работает как ты ожидаешь

Validation Plugin comments. The plugin is based on js-script jquery.validate.

WooCommerce Email Validation vs comment validation