Specifying Per-Site Policy with Chromium’s URL Filter Format

Chromium-based browsers like Microsoft Edge make very limited use of Windows Security Zones. Instead, most permissions and features that offer administrators per-site configuration via policy rely on lists of rules in the URL Filter Format. Filters are expressed in a syntax that is similar to other matching rules, but different enough to cause confusion. ForContinue reading “Specifying Per-Site Policy with Chromium’s URL Filter Format”

window.close() Restrictions

Sometimes, Web Developers are surprised to find that the window.close() API doesn’t always close the browser window. When looking at the Developer Tools console, they’ll see a message like: Scripts may close only the windows that were opened by them. Why Do Browsers Limit close()? Before we dive into what factors govern what happens whenContinue reading “window.close() Restrictions”

Font Smoothing in Edge

Update, June 2021: See the Microsoft Edge blog post. Text rendering quality is an amazingly complicated topic, with hardware, settings, fonts, differing rendering engine philosophies, and user preferences all playing key roles. In some cases, however, almost everyone can agree that one rendering is superior to another. Consider, for instance, the text of this GizmodoContinue reading “Font Smoothing in Edge”

Browser Basics: User Gestures

The Web Platform offers a great deal of power, and unfortunately evil websites go to great lengths to abuse it. One of the weakest (but simplest to implement) protections against such abuse is to block actions that were not preceded by a “User Gesture.” Such gestures (sometimes more precisely called User Activations) include a varietyContinue reading “Browser Basics: User Gestures”

A bit of GREASE keeps the web moving

For the first few years of the web, developers pretty much coded whatever they thought was cool and shipped it. Specifications, if written at all, were an afterthought. Then, for the next two decades, spec authors drafted increasingly elaborate specifications with optional features and extensibility points meant to be used to enable future work. Unfortunately,Continue reading “A bit of GREASE keeps the web moving”

Enigma Conference 2020 – Browser Privacy Panel

Brave, Mozilla Firefox, Google Chrome and Microsoft Edge presented on our current privacy work at the Enigma 2020 conference in late January. The talks were mostly high-level, but there were a few feature-level slides for each browser. My ~10 minute presentation on Microsoft Edge was first, followed by Firefox, Chrome, and Brave. At 40 minutesContinue reading “Enigma Conference 2020 – Browser Privacy Panel”

App-to-Web Communication: Launching Web Apps

In recent posts, I’ve explored mechanisms to communicate from web content to local (native) apps, and I explained how web apps can use the HTML5 registerProtocolHandler API to allow launching them from either local apps or other websites. In today’s post, we’ll explore how local apps can launch web apps in the browser. It’s Simple…Continue reading “App-to-Web Communication: Launching Web Apps”

Microsoft’s Three Browsers

It’s an interesting time. Microsoft now maintains three different web browsers: Internet Explorer 11 Microsoft Edge Legacy (Spartan, v18 and below) Chromium-based Microsoft Edge (v79+) If you’re using Internet Explorer 11, you should stop; sometimes, this is easier said than done. If you’re using Legacy Microsoft Edge, you should upgrade to the new Microsoft EdgeContinue reading “Microsoft’s Three Browsers”

Security Zones in Edge

Browsers As Decision Makers As a part of every page load, browsers have to make dozens, hundreds, or even thousands of decisions — should a particular API be available? Should a resource load be permitted? Should script be allowed to run? Should video be allowed to start playing automatically? Should cookies or credentials be sentContinue reading “Security Zones in Edge”

Retiring Internet Explorer

Prelude In late 2004, I was the Program Manager for Microsoft’s clipart website, delivering a million pieces of clipart to Microsoft Office customers every day. It was great fun. But there was a problem– our “Clip of the Day” feature, meant to spotlight a new and topical piece of clipart every day, wasn’t changing asContinue reading “Retiring Internet Explorer”