Google is bringing AMP, its cut-down version of HTML, to email. Starting today, Gmail on the Web will be able to support embedded AMP content, with support rolling out to mobile clients later ...

A Security Problem HTML-based email can be susceptible to viruses, because HTML supports JavaScript, and JavaScript is a language that activates functions.

HTMX is the HTML extension syntax that replaces JavaScript with simple markup. It could change the course of web development.

Always test your pages using Google’s own tools and third-party resources to view the rendered HTML to make sure all your content is showing up.