Microsoft Windows Internet Explorer 9 Platform Preview 2 Download

After the recent release of Internet Explorer 9 Platform Preview 1, 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 has a new set of developer samples and information about the upcoming Internet Explorer 9 web browser.


The second Platform Preview of Internet Explorer 9 shows a noticeable JavaScript speed improvements, thereby closing the gap between IE9 and Safari, Chrome, Opera, while surpassing Mozilla Firefox web browser.

See the table and the graph below for full details (data shown as released at the IE9 website):


Browser Sunspider Result Average (ms)
IE8 3746
IE9 PDC 2009 Demo 832
Firefox 3.6 736
Firefox 3.7 Pre-Release Alpha5 645
IE9 Platform Preview #1 590
IE9 Platform Preview #2 473
Safari 4.0.5 412
Chrome 371
Opera 10.52 294
Chrome 5.0.375.29 Beta 271

The Acid3 score of Internet Explorer 9 Platform Preview 2 also improved and went up to 68 out of 100. Not a perfect score but the IE9 developers have promised a better compatibility in the later releases.

The table below is a summary of the test results with the May 2010 IE Platform Preview and each of the major shipping browsers running on Windows.

Cross-browser Test Results Summary:

W3C Web Standards Number of Submitted Tests Internet Explorer 9
Platform Preview
Mozilla Firefox 3.6.3 Opera 10.52 Apple Safari 4.05 Google Chrome 4.1
HTML5 40 100% 58% 45% 38% 38%
SVG 1.1 2nd edition 31 100% 84% 94% 90% 90%
CSS3 Media Queries 19 100% 74% 68% 42% 53%
CSS3 Borders & Backgrounds 33 100% 27% 88% 27% 91%
CSS3 Selectors 16 100% 81% 63% 50% 50%
DOM Level 3 Core 18 100% 78% 78% 94% 94%
DOM Level 3 Events 30 100% 37% 33% 20% 27%
DOM Level 2 Style 5 100% 100% 80% 20% 0%

A new user string is also introduced, with the feature 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:
1. 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.
2. Version token is incremented from ‘MSIE 8.0’ to ‘MSIE 9.0’.
3. Trident token is incremented from ‘Trident/4.0’ to ‘Trident/5.0’.
4. IE9 will send the following short UA string without additions made by other software installed on the machine:


IE9’s Compatibility View UA string

Similar to IE8, IE9’s Compatibility View will map to IE7 Standards Mode, and IE9’s UA string when in Compatibility View will be:

Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Trident/5.0)

In Compatibility View, IE9 reports itself as IE7 through the application version number (Mozilla/4.0) and version token (MSIE 7.0). This is done for compatibility. An incremented Trident token, from ‘Trident/4.0’ to ‘Trident/5.0’, allows websites to distinguish between IE9 running in Compat View and IE8 running in Compat View.

The complete list of changes and resolved issues is listed in the release notes.

Web Platform

  • Features Available
    • IE9 User Agent String
    • getElementsByClassName
    • characterSet
    • CSS3 Media Queries
    • HTML5 Events
      • DOMContentLoaded
    • 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)

Download Internet Explorer 9

You can download the Internet Explorer 9 Platform Preview 2 from the official Microsoft website.

Note: Internet Explorer 9 Platform preview can be installed side by side with Internet Explorer 8. IE9 PP2 is not yet suitable for full browsing experience as it is not yet a fully functional browser, and, lacks many important browser elements, and is just a preview. Read the FAQ before installing. Read the User Guide for some useful help and tips.

System Requirements

  • Internet Explorer Platform Preview requires Windows 7 (x86 or x64) or Windows Vista SP2 (x86 or x64).
  • For Vista users, Windows Internet Explorer 8 and DirectX 2D (D2D) must be installed on your system. If you’re not already running Internet Explorer 8, download and install it first. Then install DirectX 2D by installing the Platform Update for Windows Vista, available on Windows Update. Platform Preview is only available in a 32-bit x86 version but it will install and run on 64-bit Windows 7 and Vista.

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