What Changed in Internet Explorer 8?

This article contains information about Internet Explorer 8 Beta 2. For up-to-date information, see What's New in Internet Explorer 8.

There are many new features in Windows Internet Explorer 8 that will excite both end-users and developers. Features such as Accelerators and Web Slices enhance the user experience, while the improved Phishing Filter helps keep users safe. For developers, strong Cascading Style Sheets (CSS) and HTML compatibility, enhancements to ActiveX controls, and greater Asynchronous JavaScript and XML (AJAX) interoperability provide opportunities to bring new experiences to users.

Features for Users


Accelerators are contextual services that quickly access a service from any Web page. Because users typically copy and paste from one Webpage to another, Windows Internet Explorer 8 Accelerators has made this common pattern easier to do.

The Accelerators feature performs two main functions: it "looks up" information within a Web page and "sends" Web content to a Web application. For example, a user is interested in a restaurant and wants to see its location. During this "look up," the user selects the address and views an in-place map, using his favorite map service.

An example of a "send" Accelerator is a user reads an interesting article and wants to blog about a portion of it. The user selects the portion and uses the blog Accelerator. This navigates to the user’s blog site, with the selection already available in the edit field.

Accelerators are services that the user can install and manage. Users can install them from the Windows Internet Explorer 8 Service Guide or through any Website that advertises Accelerators.

Web Slices

The Web Slice is a new feature in which Web pages connect to their users by subscribing to content directly within a Webpage. Web Slices behave just like feeds, where clients can subscribe to get updates and are notified of changes.

Windows Internet Explorer 8 users can discover Web Slices within a Webpage and add them to the Favorites bar, a dedicated row below the Address bar for easy access to links. Windows Internet Explorer 8 subscribes to the Webpage, detects changes in the Web Slice, and notifies the user of updates. Users can preview these updates directly from the Favorites bar and click through the Website to get more information. For example, a Web Slice could be used for an item up for auction on an auction site. A Web Slice on the page would let you subscribe to receive updates on a set-time basis and notify you of price changes.

Favorites Bar

In Windows Internet Explorer 7, the Links bar provided users with one-click access to their favorite sites. For Windows Internet Explorer 8, the Links bar has undergone a complete makeover. It has been renamed the Favorites bar to enable users to associate this bar as a place to put and easily access all their favorite Web items, such as links, feeds, and Web Slices as well as documents in Word, Excel, and PowerPoint.

A user can easily add a link to the Favorites bar by using the Add to Favorites button and selecting the Add to Favorites Bar option.

Automatic Crash Recovery

The Automatic Crash Recovery (ACR) feature of Windows Internet Explorer 8 can help prevent the loss of work and productivity in the unlikely event that the browser crashes or hangs. The ACR feature takes advantage of the Loosely-Coupled Internet Explorer feature to provide new crash recovery capabilities, such as tab recovery, which will minimize interruptions to users’ browsing sessions.

See Automatic Crash Recovery white paper for more information.

Improved Phishing Filter

Windows Internet Explorer 7 introduced the Phishing Filter, a feature that helped warn users when they visited a phishing site, that is, a spoof of a trusted legitimate site with the intention of stealing the user’s personal or financial information. For Windows Internet Explorer 8, Microsoft built on the success of the Phishing Filter with a more comprehensive feature called the SmartScreen Filter.


Features for Developers


In response to the increase of user interface (UI) complexity on the Web, the Web Accessibility Initiative World Wide Web link group has defined a roadmap for Accessible Rich Internet Applications (ARIA), which introduces ways for Web site authors to define how custom UI elements are accessed. ARIA accomplishes this by defining a set of HTML attributes that map back to common UI controls. As a result, users with disabilities can access Web sites with a rich interaction model. By exposing ARIA through the Microsoft Active Accessibility API in Windows Internet Explorer 8, assistive technologies that already use Active Accessibility can also support ARIA easily.

The alt attribute is no longer displayed as the image tooltip when the browser is running in IE8 Standards mode. Instead, the target of the longDesc attribute is used as the tooltip if present; otherwise, the title is displayed. The alt attribute is still used as the Active Accessibility name, and the title attribute is used as the fallback name only if alt is not present.

For more information, see What's New for Accessibility in Internet Explorer 8.

ActiveX Improvements

Windows Internet Explorer 8 offers greater control over who can install Microsoft ActiveX controls and on which sites they are allowed to run.

Per-site ActiveX

  • Nearly half of all ActiveX controls meant to run on only one site do not use any form of site-locking technology. This means that many controls are not secure by default and could be misused by malicious Web sites. To prevent this, Windows Internet Explorer 8permits users to decide whether to allow ActiveX controls to run on a site-by-site basis.

Non-administrator installation

  • Standard users (i.e., those without administrator privileges) can install ActiveX controls to their user profiles without a UAC prompt or administrator involvement of any kind. In the event that a user does install a malicious ActiveX control, only the user profile is affected; the system itself is not compromised.

AJAX Enhancements

AJAX is changing the way Web applications are built. Windows Internet Explorer 8 brings new functionality to the XMLHttpRequest object that enables AJAX applications. These functions include:

  • AJAX Navigation. Client requests that do not trigger traditional page navigation can now update the property, which allows the button to function appropriately.
    • Connection Events. Where reliability is of top concern, AJAX applications can exit gracefully if the call is canceled or times out.
    • Cross-Domain Request (XDR).To address the limitations of existing mashup development, Windows Internet Explorer 8 introduces the XDomainRequest object to allow restricted and secure communication between untrusted modules in the page. The browser shields the user from potential threats, while allowing powerful cross-site interaction.
    • Cross-Document Messaging. Documents in different domains can securely exchange data using .
    • More Connections. Windows Internet Explorer 8 raises the number of connections per host by default, for a potential drop in page load times and increased parallelism in AJAX scenarios.

For more information, see the following documents.

CSS Compliance

Windows Internet Explorer 8 is the most CSS-compliant release yet. Here are some highlights.

  • Data Uniform Resource Identifier(URI).This mechanism allows Web page authors to embed small entities directly within a URI, rather than using the URI to identify a location from which to retrieve the entity. This is primarily of interest for small images (such as bullets) used within CSS or layout.
  • New Pseudo-Classes. The following are new to Windows Internet Explorer 8:

:before and :after pseudo-elements allow authors to specify the location of dynamic content relative to an element’s document tree content.

:focus refers to when a user makes an element active so it can perform its task. This pseudo-class applies while an element has input focus.

Outline  enables elements to be highlighted without affecting their size.  It is a shorthand property for  outline-color,  outline-style,  and  outline-width.

Printing. The following properties have been added to ease printing:

  1. page-break-inside
  2. widows
  3. orphans

Table Layouts. For many years, tables were the preferred layout mechanism on the Internet. With Windows Internet Explorer 8, it is now possible to apply table-style formatting to non-table elements, using the display attribute. In practice, CSS tables are more permissive than HTML markup; tables created with CSS rules will nest elements to become valid, whereas tables created with HTML will close containers to avoid unexpected nesting.

For more information, read the following documents.

Developer Tools

Windows Internet Explorer 8’s enhanced Developer Tools expose the internal elements of Web pages to help research and resolve problems involving HTML, CSS, and script. The tools included are as follows:

  • CSS tool, which displays various rules defined by style sheets that are loaded by your Web page.
  • Script debugging, a built-in lightweight debugger that lets you set breakpoints and step through client-side script without leaving Windows Internet Explorer.
  • Version mode switching, which allows you to switch into different browser modes to test content for standards compliance.
  • Profiler, a built-in tool to show where the browser spends most of its time in execution so Web page authors can focus optimizations.

For more information, read the following documents.

Document Compatibility Mode

Windows Internet Explorer 8 has made deliberate investments in building a new layout engine with full CSS 2.1, strong HTML 5 support, and interoperability fixes for the Document Object Model (DOM). The highest level of standards support is on by default. Website authors can select EmulationIE7 mode rendering in Windows Internet Explorer 8 with the following META tag:

<meta http-equiv="X-UA-Compatible" content="IE=EmulateIE7" />

For more information, read the following documents.

DOM Storage

Storing Web application data within a local cache opens up new possibilities for a future class of Web applications by storing and loading user data directly onto a user's hard drive. The future of AJAX will extend its reach beyond client-server interactions and into local data storage that is addressed from any Web page and interpreted by the client Web browser. A Web application can write to local storage when disconnected from the Internet and synchronize local changes when an active Internet connection returns. A scriptable online-offline connectivity event fires on connection-status change and will be available to all pages.

See also Introduction to DOM Storage.

HTML Improvements

The new HTML 4.01 implementation is now much more interoperable. These improvements include the following:

  • The tag image fallback is interoperable with other browsers. For example, an tag without dimensions is now the same size as the image instead of 0 x 0 pixels.
  • The element submits its attribute instead of its , which means the element for cross-browser scenarios can now be used.
  • The method is now case sensitive and no longer searches incorrectly using the attribute.
  • The method is now case insensitive, which means "camel case" (e.g., "camelCaseWord") is no longer necessary to specify attributes. It also correctly identifies HTML attributes such as and .

For more information, read the following documents.

Protected Mode Cookies

Protected Mode restricts file writes to low-integrity locations, including cookies. In Windows Internet Explorer 8, medium-integrity applications can access low-integrity cookies without user interaction by using:

As always, applications that use cookies downloaded from the Internet should assume these cookies contain malicious data.

Selectors API

Use the power of CSS selectors to rapidly locate DOM elements. The API introduces two methods, selectElement and selectAllElements, that take a selector (or group of selectors) and return the matching DOM elements. With these methods, it is easier to match a set of element nodes based on specific criteria. The Selectors API provides significantly faster performance over non-native implementations.

For more information, see Selecting Objects With JavaScript.

Tab Isolation and Concurrency

In Windows Internet Explorer 8, the browser frame is "loosely-coupled" with the tabs inside it. This means that pages that use Protected Mode as well as those that don't may be hosted within the same instance of the browser. Additionally, glitches and hangs don't bring down the entire browser, thereby ensuring that poorly written extensions do not significantly impact the performance or reliability of Windows Internet Explorer 8.