A quick introduction to Internet Explorer 9

On 16 March, Microsoft unveiled a first web browser, Internet Explorer 9 pre-release. IE 9 current user interface is far from comprehensive: it has no buttons or address bar "Back" and "next". Indeed, this version is intended for developers, and its purpose is to show the heart of the next version of the browser. Among the enhancements it retains mainly graphics performance and improved JavaScript, and the new web standards support.

Improved performance current versions of Internet Explorer are very overdue level performance relative to their competitors, either in terms of speed of rendering or JavaScript. With this new version, Microsoft attempts to improve these two points.

A new JavaScript engine JavaScript scripts used on the web are increasingly heavy and their performance has become a major concern for developers of web browsers. To ensure that the scripts run fast enough, browsers had to change of approach to the use of a simple interpreter: Firefox and chrome, with TraceMonkey and V8 partially compile JavaScript code for faster execution.

IE8 was only using a simple interpreter, and its performance was indented relative to those of other browsers. IE 9 developers have therefore coded a new JavaScript engine called Chakra. It compiles the JavaScript in the background, while scripts are executed by a shell: This allows you to run scripts when the page loads, and take advantage of machines with multiple processors. JavaScript is a language for dynamic typing: types of variables are determined at runtime. This slows the scripts, and that is why the JavaScript engine tries to guess the maximum of information on the types at compile time.

User picture in addition to accelerated heart language, developers have also optimized functions JavaScript libraries: manipulation of arrays of strings or regular expressions. Indeed, these functions are much used, and their performance is also a key element to run scripts quickly. These efforts have paid off, since according to the SunSpider test, IE 9 runs the JavaScript more than 5 times faster than IE 8 and moves before Firefox 3.7 alpha version.


Accelerated by the rendering of web pages graphics drawing has also been optimized: IE 9 takes part of the new graphics features introduced in Windows Vista. With Direct2D, a large part of the drawing operations which were previously performed by the processor can be delegated to the graphics card. The text is drawn through DirectWrite, which enables also the graphics acceleration.

This change improves actually performance, as shown in the demos on the site with Internet Explorer 9. However, Direct2D and DirectWrite are not available for Windows XP, so that IE 9 will be available only from Windows Vista: users of older versions will have to remain at version 8.


Support for this version, IE developers web technologies have also improved support for web standards: the aim is that same code gives the same result in all browsers. Already, with IE 8, Microsoft had added a rendering mode, the standards mode, the web standards much more environmentally friendly with for example better support for CSS than its predecessors. IE 9 continues in this way, as evidenced by his score to the Acid 3 test which is passed to 55/100 for IE 9, against 20/100 for IE 8.

But this version also adds support for web standards that were already available from competitors.

The vector drawing with SVG image user we announced early January that Microsoft had asked to join the W3C SVG Working Group on the internet blog. This accession resulted in fact, since the new version of the browser will include support for this format.
SVG is an XML-based vector drawing format: instead of encoding an image as an array of colored pixels, a vector drawing is represented by a set of lines and shapes. Thus, enlarge these images without loss of quality. In addition, it is possible to manipulate SVG with JavaScript images: can this way creating games, animations,...

In this pre-release, SVG support is still very partial, but developers have plans to add missing features. As with HTML, the SVG rendering is accelerated by the graphics card.

HTML5, DOM and CSS 3 this pre-release also includes a partial support of CSS3 and HTML5, like Vinageer, the latest versions of HTML and CSS. An example that will appeal to many developers is adding the CSS border-radius property allows you to create very easily rounded corners without using images. New appeared in CSS 3 selectors are also supported.

It can also noted many additions to the DOM API that allows to manipulate web pages from JavaScript. For example, DOM events are better supported, as well as DOM style, which allows you to dynamically manipulate style sheets.

Finally, developers have announced, although support is not included in this version, IE 9 will include sound or video in an external webpage without plugin, and control directly in JavaScript while using tags video and audio. Microsoft has chosen to use protected by patents, rather than free-form Theora, H.264 video format for this tag.

The future of web?

It regretted the absence of the canvas, item that allows you to draw images using JavaScript. However, the final version of Internet Explorer 9 should emerge in 2011: this leaves a lot of time developers to add new features.

This version includes support for many technologies that could greatly simplify life for web developers, with better support for web standards and new tags. Unfortunately, Internet Explorer 9 is not available for Windows XP, which may considerably hinder its adoption. If they want to make sites accessible to everyone, developers will not so use these new features before a few years.