When you embed an HTML form into a page, you may want it to submit in a new window. This way, when someone subscribes, the confirmation message opens in a new page rather than replacing the current one and your subscriber doesn't leave the page he was visiting.
To do so, simply add a target="_blank" attribute to the form tag.
Code sample:
<form target="_blank" action="https://app.cyberimpact.com/optin" method="post" accept-charset="utf-8">