Tag Archives: Chromium

MHTML in Chromium

The MHTML file format (aka “Webpage, single file”) allows a single file to contain the multiple resources that are used to load a webpage (script, css, images, etc). Edge (Chromium) has an option to use the format when saving the current page via Ctrl+S or the Save page as… menu command: … but the browser’sContinue reading “MHTML in Chromium”

Download Blocking by File Type

Last Updated: 20 May 2024 I’ve previously gushed about the magic of the File Type Policies component — a mechanism that allows files to be classified by their level of “dangerousness”, such that harmless files (e.g. .txt files) can be downloaded freely, whilst potentially-dangerous files (e.g. .dll files) are subjected to a higher degree ofContinue reading “Download Blocking by File Type”

Per-Site Permissions in Edge

Last year, I wrote about how the new Microsoft Edge browser mostly ignores Security Zones (except in very rare circumstances) to configure security and permissions decisions. Instead, in Chromium per-site permissions are controlled by settings and policies expressed using a simple syntax with limited wildcarding support. Settings Page’s Site Permissions and Group Policy Internet ExplorerContinue reading “Per-Site Permissions in Edge”

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”

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”

Client Certificates and Logout

Last Updated May 16, 2022 Back in May 2020, I wrote about Client Certificate Authentication, a mechanism that allows websites to strongly validate the identity of their visitors using certificates presented by the visitor’s browser. One significant limitation for client certificate authentication is that there is no standards-based mechanism for a user to “log out”Continue reading “Client Certificates and Logout”

Debugging Browsers – Tools and Techniques

Last update: November 14, 2023 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”

Analyzing Network Traffic Logs (NetLog json)

Previously, I’ve described how to capture a network traffic log from Microsoft Edge, Google Chrome, and applications based on Chromium or Electron. In this post, I aim to catalog some guidance for looking at these logs to help find the root cause of captured problems and otherwise make sense of the data collected. Last Update:Continue reading “Analyzing Network Traffic Logs (NetLog json)”

Debugging Proxy Configuration Scripts in the new Edge

I’ve written about Browser Proxy Configuration a few times over the years, and I’m delighted that Chromium has accurate & up-to-date documentation for its proxy support. Chromium’s PAC fetching code (and the code that calls it) is also quite readable with many comments. One thing I’d like to call out is that Microsoft Edge’s newContinue reading “Debugging Proxy Configuration Scripts in the new Edge”