Compressing the Web

Be succinct. Virtually any network-based application can be made faster by optimizing the number of bytes transferred across the network. Taking advantage of caching is a great way to minimize transfer sizes, but just as important is to reduce the size of the resources you transfer. Data compression is used throughout the protocols and formats…

5

Unicode in URL changes for IE11

I wrote a bit about Internet Explorer’s International Settings back in July of 2012. Internet Explorer 10 and 11 quietly brought some changes: In IE10, the Use UTF-8 for mailto links option was removed. In IE11, the misleadingly-named Send UTF-8 URLs option is renamed to correctly reflect its function (Send URL path as UTF-8) and…

6

Proxy-Authentication breaks many applications

When I first joined Office, I worked on the team responsible for delivering Help, Templates, and ClipArt into the client applications. As we were testing our work in various simulated customer environments, we found a big problem. At least one big customer (tens of thousands of licenses) had a network environment in which their users…

6

The Hazards of Browser Quirks, continued

My First Law of Browser Quirks was introduced a while ago: If there’s a way for a site to take dependency on a browser quirk, and break if that quirk is removed, it will happen. The Second Law of Browser Quirks is: If there’s a way for a site to combine a set of browser…

1

URL Components in the DOM

The IE team has been working our way through the remaining issues reported from internal and external testing of the IE9 Release Candidate. In the course of investigating one recent internal-site compatibility bug, I ran across an interesting interoperability issue that appears to have existed since IE5 (or earlier). It isn’t well-documented, even as it…

2

Troubleshooting Authentication with Fiddler

Over the last few weeks, I’ve been exchanging mail with a webmaster (Vladimir) in Russia who reported that his customers were having problems using IE8 on Windows 7 to log into his website. His site uses HTTP Basic Authentication, so users are prompted to enter their credentials using the following dialog: I asked the webmaster to…

6

HTML5 Implementation Issues in IE8 (and later)

IE8 introduced support for some of the more stable features in the HTML5 spec. However, web developers have reported some problematic scenarios in IE8’s support for these features, as described below. 1. postMessage only works for IFRAMES/FRAMES The HTML5 postMessage function provides a great way for mutually distrusting documents (even cross-domain) to communicate securely and with high performance and…

12

Internet Explorer Cookie Internals (FAQ)

Over the five years I’ve worked on Internet Explorer, I’ve probably seen more questions from the community about HTTP cookies than on any other topic. Cookies are an integral component of most websites in use today, and hence problems or unexpected behaviors with cookies tend to get a lot of attention. In this post, I’ll…

67

Bugs in IE8’s Lookahead Downloader

All bugs mentioned in this post are now fixed.  Internet Explorer has a number of features designed to render pages more quickly. One of these features is called the “Lookahead Downloader” and it’s used to quickly scan the page as it comes in, looking for the URLs of resources which will be needed later in the rendering…

116