Accessibility (UIA) Troubleshooting

Chromium-based browsers offer a number of accessibility-related features. When you visit about:accessibility, you can see more about the state of these features (similarly, you can find the states in about:histograms/Accessibility.ModeFlag). You can enable features via the Accessibility page, or by You can also passing the command line argument –force-renderer-accessibility into the browser. In some cases,Continue reading “Accessibility (UIA) Troubleshooting”

Practical Time Machines

Many “emergency” situations in our modern world would’ve been easy to fix had they been foreseen in advance. If only we’d known what was going to happen, the badness could’ve easily been prevented. Unfortunately, when problems are discovered only “as they happen” in production, everyone must race to minimize the damage and put out theContinue reading “Practical Time Machines”

Simply Making Simple Fixes Simple for Chromium

Google recently introduced a cool web-based editing tool for Chromium source code, a very stripped down version of the Willy Wonka tooling Googlers get to use for non-Chromium projects. I’ve used this tool to submit two trivial change lists (CLs, aka PRs) to Chromium, but I was curious about whether this new feature would workContinue reading “Simply Making Simple Fixes Simple for Chromium”

Debugging Browsers – Tools and Techniques

Last update: March 29, 2021 Earlier this year, I shared a post on how you can become an expert on web browsers from the comfort of your desk… or anywhere else you have an internet connection. In that post, I mostly covered how to search through the source, review issue reports, and find design documentation.Continue reading “Debugging Browsers – Tools and Techniques”

Web Debugging: Watching Element Changes

Recently, I was debugging a regression where I wanted to watch change’s in an element’s property at runtime. Specifically, I wanted to watch the URL change when I select different colors in Tesla’s customizer. By using the Inspect Element tool, I can find the relevant image in the tree, and then when I pick aContinue reading “Web Debugging: Watching Element Changes”

Browser Memory Limits

Web browsers are notorious for being memory hogs, but this can be a bit misleading– in most cases, the memory used by the loaded pages accounts for the majority of memory consumption. Unfortunately, some pages are not very good stewards of the system’s memory. One particularly common problem is memory leaks– a site establishes aContinue reading “Browser Memory Limits”

Web-to-App Communication: The Native Messaging API

One of the most powerful mechanisms for Web-to-App communication is to use an extension that utilizes the NativeMessaging API. The NativeMessaging API allows an extension running inside the browser to exchange messages with a native-code “Host” executable running outside of the browser sandbox. That Host executable runs with the full privileges of the current userContinue reading “Web-to-App Communication: The Native Messaging API”

Seamless Single Sign-On

There are many different authentication primitives built into browsers. The most common include Web Forms authentication, HTTP authentication, client certificate authentication, and the new WebAuthN standard. Numerous different authentication frameworks build atop these, and many enterprise websites support more than one scheme. Each of the underlying authentication primitives has different characteristics: client certificate authentication isContinue reading “Seamless Single Sign-On”

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”