ericlaw

Edge Interop Issues

As we finish up the next release of Windows 10 (Fall 2018), my team is hard at work triaging incoming bugs. Many such bugs take the form “Edge does the wrong thing for this page. ${Other_Browser} works okay.” This post is designed to be an (ever-growing) index of some of the behavioral deltas that areContinue reading “Edge Interop Issues”

Script-Generated Download Files

As we finish up the next release of Windows 10, my team is hard at work triaging incoming bugs. Here’s a pattern that has come up a few times this month: Bug: I click download in Edge Legacy: …but I end up on an error page: Womp womp. If you watch the network traffic, you’llContinue reading “Script-Generated Download Files”

CORS and Vary

Yesterday, I started looking a site compatibility bug where a page’s layout is intermittently busted. Popping open the F12 Tools on the failing page, we see that a stylesheet is getting blocked because it lacks a CORS Access-Control-Allow-Origin response header: We see that the client demands the header because the LINK element that references itContinue reading “CORS and Vary”

Be skeptical of client-reported MIME Content-Types

Over the 14 years that I’ve been working on browsers and the web platform, I’ve seen a lot of bugs where the client’s configuration causes a problem with a website. By default, Windows maintains File Extension to Content Type and Content Type to File Extension mappings mappings in the registry. You can find the former mappings inContinue reading “Be skeptical of client-reported MIME Content-Types”

Edge EV UI Requires SmartScreen

A user recently noticed that when loading Paypal.com in Microsoft Edge, the UI shown was the default HTTPS UI (a gray lock): Instead of the fancier “green” UI shown for servers that present Extended Validation (EV) certificates: The user observed this on some Windows 10 machines but not others. The variable that differed between those machines wasContinue reading “Edge EV UI Requires SmartScreen”