HTML elements that deserve to be deprecated immediately
Over the last three decades, HTML has evolved into a robust structure. But along the way, we kept some garbage in the specification for the sake of backwards compatibility. It is time to let them go.
Exhibit A: The iframe. It's a security nightmare, completely un-stylable, and acts as a massive page speed block because it mounts an entire nested browser window inside your layout. There is almost always a cleaner way to fetch and display third-party content. Let it die.
Deep Dive
Exhibit B: The marquee tag. Yes, I know it's deprecated already, but developers still write custom JavaScript wrappers to simulate marquee banners (myself included on the Home page, but at least ours uses CSS transitions and contains jokes!).
Let's write cleaner, simpler markups. The less legacy code we rely on, the more secure and performant our pages will be.