I’m passionate about building tools that help developers and testers discover, analyze, and fix problems with their sites. Some of the first code I ever released was a set of trivial JavaScript-based browser extensions for IE5. I later used the more powerful COM-based extensibility model to hack together some add-ons that would log ActiveX controlsContinue reading “Building the moarTLS Analyzer”
Category Archives: browsers
On Daylight Savings Time
In Fiddler, the Caching tab will attempt to calculate the cache freshness lifetime for responses that lack an explicit Expires or Cache-Control: max-age directive. The standard suggests clients use (0.1 * (DateTime.Now – Last-Modified)) as a heuristic freshness lifetime. An alert Fiddler user noticed that the values he was seeing were slightly off what he expected: sometimes the valuesContinue reading “On Daylight Savings Time”
Things I’ve Learned in my first weeks on Chrome
This is a stub post which will be updated periodically. It would be impossible to summarize how much I’ve learned in the last six weeks working at Google, but it’s easy to throw together some references to the most interesting and accessible things I’ve learned. So that’s this post. Developing Chrome Searching the code isContinue reading “Things I’ve Learned in my first weeks on Chrome”
Web Developers and Footguns
If you offer web developers footguns, you’d better staff up your local trauma department. In a prior life, I wrote a lot about Same-Origin-Policy, including the basic DENY-READ principle that means that script running in the context of origin A.com cannot read content from B.com. When we built the (ill-fated) XDomainRequest object in IE8, weContinue reading “Web Developers and Footguns”
Leaking Keystrokes
Windows 10’s IE11 continues to send your keystrokes over the internet in plaintext as you type in the address bar, a part of the “Search Suggestions” feature: “But I don’t search from the address bar,” you might say. That may be, but if you fail to type or paste a URL (sans protocol) into theContinue reading “Leaking Keystrokes”
Extended Validation Certificates – The Introduction
In 2005, one of my first projects on the Internet Explorer team was improving the user-experience for HTTPS sites (“SSLUX”). Our first task was to change the certificate error experience from the confusing and misleading modal dialog box: … to something that more clearly conveyed the risk and which more clearly discouraged users from acceptingContinue reading “Extended Validation Certificates – The Introduction”
Automatically Evaluating Compressibility
Fiddler’s Transformer tab has long been a simple way to examine the use of HTTP compression of web assets, especially as new compression engines (like Zopfli) and compression formats (like Brotli) arose. However, the one-Session-at-a-time design of the Transformer tab means it is cumbersome to use to evaluate the compressibility of an entire page orContinue reading “Automatically Evaluating Compressibility”
Putting Users First
When I worked on Internet Explorer, the team was proud of the fact that we could claim to be more aligned with our users’ goals than either of our major competitors (both of whom were funded almost entirely by advertising). IE, the story went, was paid for by users who purchased Windows, and thus ourContinue reading “Putting Users First”
My Next Adventure
Back in 2004, I couldn’t get the tiny IE team interested in fixing caching bugs that were causing my team’s website to break in bizarre and unpredictable ways. I figured I’d hop over there, fix some bugs, and move along. I quickly realized that I was hopelessly in love with browsers in general and securityContinue reading “My Next Adventure”
The Sad State of HAR
Spring 2017 Update: Some of these issues have been fixed. The HTTP Archive Format (HAR) was designed to allow tools to exchange network traffic using a standard format; this format is akin to Fiddler’s Session Archive Zip format but is supported natively by browser developer tools. Unlike SAZ files, it is not compressed by default,Continue reading “The Sad State of HAR”
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