Microsoft delivers IE8 release candidate

As expected, Microsoft Monday launched a release candidate of Internet Explorer 8, the first update to the browser since last August.

The build, dubbed IE8 Release Candidate 1, runs on Windows XP, Vista, Server 2003 and Server 2008, but not on the two-week-old Windows 7 beta .

While Windows 7's preview includes a version of IE8, it's actually a interim build, somewhere between the Beta 2 of five months ago and today's RC1, said James Pratt, a senior product manager on the IE development team. "It's a pre-RC of IE that we specifically tuned for the new features in Windows 7, such as jump lists and touch support," he said.

Because of its reliance on Windows 7-only features, IE8's release candidate will require additional testing to qualify on that operating system, said Pratt, who declined to give a timetable for when the Windows 7 version will be ready, or when IE8 will be synchronized across all versions of Windows. "That depends on the development cycle progress," Pratt said. "We don't have a plan that we can talk about."

Nor would Pratt set a release date for a final shipping version of the browser. "The release date will be defined by the feedback we receive," he said, also declining to say whether today's build would be the sole release candidate and, if not, how many Microsoft expects.

That may be a clue that Microsoft has changed its plans. Back in November, for example, IE's general manager, Dean Hachamovitch, said that the company would roll out just "one more public update" of the browser before following that "with the final release."

Questions of IE8 RC1's place in the road map aside, Pratt said that the build is "platform-complete, feature-complete," which means Microsoft doesn't anticipate adding or subtracting any features from the build.

It does sport changes from Beta 2, which Microsoft unveiled last August, however, including one that Hachamovitch touted last month when he said IE8 RC was "just around the corner" and urged Web developers to get ready to test their sites and services with the new browser.

"We're shipping IE8 RC1 with list of sites that we have learned through feedback that should be run in compatibility mode," said Pratt, echoing Hachamovitch's news last month of a feature that will automatically engage IE8's backward-compatibility mode and render sites on that list as IE7 does.

The release candidate also includes several user interface tweaks -- IE8 no longer searches through RSS feeds by default when users type in text in the address bar -- and a new security tool that Pratt said protects users from "clickjacking" attacks.

Clickjacking is the term given to a new class of browser-based attacks last September to describe tactics that can be used by hackers and scammers to hide malicious actions under the cover of a legitimate site.

While Mozilla's Firefox can be protected against clickjacking attacks by installing the "NoScript" add-on , IE8 RC1 includes build-in anti-clickjacking technologies, said Prat. He declined to reveal how they work, saying that Microsoft would disclose more information in future posts on its IE blog.

Pratt also claimed that IE8 RC1 is faster than the last public preview, Beta 2. But like Hachamovitch, he dismissed the benchmark bragging of competitors such as Mozilla and Google Inc., which have trumpeted JavaScript test scores for Firefox and Chrome, respectively, for months. Pratt even used the same term -- "drag race" -- to describe what Microsoft thought of JavaScript benchmarking.

"We took a critical look at performance, and looked at when users load real Web pages," said Pratt, arguing that Microsoft's internal tests are more realistic than JavaScript benchmarks such as SunSpider. "IE only spends about 20% of its time handling JavaScript," said Pratt, "and 80% doing other things, like processing [cascading style sheets]. To us, it seemed like we could deliver better performance if we focused holistically. To say that a browser engine is just a JavaScript [engine] doesn't match the reality of how the Web is built today.

"We're at the point, with what people do in the browser, that users can't really tell the difference between browser [performance]," he said.

Users who have already installed a beta of IE8 will soon be offered an upgrade to RC1 automatically via Windows Update, said Pratt. Others, or the impatient, can download the release candidate from the company's Web site.