Internet Explorer Platform Preview 2 Download

Martin Brinkmann
May 5, 2010
Updated • Dec 9, 2012
Internet Explorer

Microsoft has just released a new Internet Explorer Platform Preview that is available for download at the Internet Explorer 9 website. Microsoft has also added a testdrive site that contains a new set of developer samples and information about the upcoming Internet Explorer 9 web browser.

The second preview of Internet Explorer 9 continues to show JavaScript speed improvements over previous versions closing the gap between IE9 and Safari, Chrome and Opera and surpassing the Firefox web browser.

Dean Hachamovitch, General Manager, Internet Explorer points out that most of the performance improvements can be attributed to improvements in subsystems of the Internet Explorer 9 web browser and not specific JavaScript tuning.

The Acid3 score of Internet Explorer 9 went up to 68 out of 100. Not a perfect score by all means but the developers promise better compatibility in later releases. They do mention that the Acid3 test needs some revamping in their opinion.

A new user string is introduced as well as the capability to change the user agent string in the preview version of IE9.

IE9’s default UA string

There are four changes to IE8’s UA string that site developers need to be aware of:

Application version is incremented from ‘Mozilla/4.0’ to ‘Mozilla/5.0’ to match other browsers (explained well in the great History of the user-agent string post). This change signals that IE9 is an interoperable browser.
Version token is incremented from ‘MSIE 8.0’ to ‘MSIE 9.0’.
Trident token is incremented from ‘Trident/4.0’ to ‘Trident/5.0’.
IE9 will send the following short UA string without additions made by other software installed on the machine:

ie9 user agent

Internet Explorer 9 Platform preview installs side by side with Internet Explorer 8. It is not suited yet for general purpose browsing as it is missing many major components including UI elements but also security protections.

The complete list of changes is listed in the release notes in the What's new section.

Web Platform

Features Available

  • IE9 User Agent String
  • CSS3 Media Queries
  • HTML5 Events
  • DOM Core
    DocumentType, ProcessingInstruction, createDocument
  • DOM Traversal
  • DOM L3 Events
    DOMAttrModified, Composition events

Features Partially Implemented

  • DataURI
    Support in script source
    Developer Tools

Features Available

  • User Agent String Picker
    A new tool that can be used to change the user agent string that IE sends with every request. The tool comes with some built in presets and new custom user agent strings can be added.
  • Console Tab
    The console window is now a full tab and has been expanded to include the logging of diagnostic information from IE.
  • Network inspection improvements
    Shortened URL
    Color coding for errors
    Scaling units (eg. 500 ms becomes 0.5 s)

You can download the Internet Explorer 9 Platform Preview from the official Microsoft website. Remember that it requires either Windows 7 or Windows Vista SP2 and Internet Explorer 8 before it can be installed.


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  1. George said on May 6, 2010 at 8:42 pm

    I’ve been testing IE9 with SVG and Canvas, and I gotta say, it definitely feels a lot more snappy than Firefox. It sometimes even feels faster than Chrome, but, in my opinion, Opera is still faster with SVG/Canvas and javascript, but not by much. When IE9 comes out, IE might even take back the title of best browser, if they can work out a good user interface with add-ons Firefox-style.

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