We dont want to block all HTML emails, but just ones that use javascript, or attach javascript, or anything to do with javascript. Is there a way to do that right at the server?

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. Google has come a long way with rendering JavaScript.

To manipulate SVG using JavaScript, we can embed the SVG graphic in the document that contains the JavaScript or embed the JavaScript in the SVG code.