HTML Concepts: Browsing Contexts

Published on Sep 30, 2022 (updated Oct 18, 2024), filed under development, html. (Share this post, e.g., on Mastodon or on Bluesky.)

Welcome to another episode of HTML Concepts! Today, browsing contexts—what is that?

The starting point should be the HTML specification (as always—this, and not even MDN, is the source of truth). What does it say?

A browsing context is an environment in which Document objects are presented to the user.

This is cryptic, but the specification goes on to clarify:

A tab or window in a web browser typically contains a browsing context, as does an iframe or frames in a frameset.

This sounds fundamental and indeed, the browsing context is a key concept:

A browsing context is where a user agent displays a document—which often is a tab or window, but can also be an iframe or frame. Every browsing context has its own DOM, origin, navigation and history, as well as cookies.

That is, every site or app has a and its own browsing context—and that’s why this is such an important, yet also basic concept.

I’m not sure I made a much more complex subject overly simple, or a simple subject overly complex! Please let me know.

About Me

I’m Jens (long: Jens Oliver Meiert), and I’m an engineering lead, guerrilla philosopher, and indie publisher. I’ve worked as a technical lead and engineering manager for companies you use every day (like Google) and companies you’ve never heard of, I’m an occasional contributor to web standards (like HTML, CSS, WCAG), and I write and review books for O’Reilly and Frontend Dogma.

I love trying things, not only in web development and engineering management, but also with respect to politics and philosophy. Here on meiert.com I talk about some of my experiences and perspectives. (Please share feedback: Interpret charitably, but do be critical.)