Standards by Default: What Does It Mean?

The Web has matured to the point where standards help unify everyone’s Web experience. Windows Internet Explorer 8 is set to the highest level of current standards from the outset. By default, Windows Internet Explorer 8 will attempt to display content using its most standards-compliant mode, the IE8 Standards mode. Many sites on the Internet have been optimized for Windows Internet Explorer 7 or a previous version. To allow existing site content to become compatible within Windows Internet Explorer 8, site operators may designate the correct layout mode for Windows Internet Explorer 8 clients via a new compatibility mode switch. This mode switch may be used on a per-site (specified via the server response header) or per-page basis (specified in each page of content). The document compatibility mode ties a Web page to the behavior of a specific version of Windows Internet Explorer.

Setting Windows Internet Explorer Version

Windows Internet Explorer 8 supports a number of document compatibility modes that enable different features and can affect the way content is displayed.

Mode	Description
IE5	Renders content as if it were displayed by Windows Internet Explorer 7Quirks mode, which is very similar to how Windows Internet Explorer 5 displayed content.
IE7	Renders content as if it were displayed by Windows Internet Explorer 7's Standards mode, whether or not the page contains a <!DOCTYPE> directive.
Emulate IE7	Tells Windows Internet Explorer to use the <!DOCTYPE> directive to determine how to render content. Standards mode directives are displayed in Windows Internet Explorer 7 Standards mode, and Quirks mode directives are displayed in IE5 mode. Unlike IE7 mode, Emulate IE7 mode respects the <!DOCTYPE> directive. For many Web sites, this is the preferred compatibility mode.
IE8	Provides the highest support available for industry standards, including the W3C Cascading Style Sheets Level 2.1 Specification and the W3C Selectors API, as well as limited support for the W3C Cascading Style Sheets Level 3 Specification (Working Draft).
Edge	Tells Windows Internet Explorer to display content in the highest mode available. With Windows Internet Explorer 8, this is equivalent to IE8 mode. If a future release of Windows Internet Explorer supported a higher compatibility mode, pages set to Edge mode would appear in the highest mode supported by that version; however, those same pages would still appear in IE8 mode when viewed with Windows Internet Explorer 8. Because Edge mode documents display Web pages using the highest mode available to the version of Windows Internet Explorer used to view them, it is recommended that you limit their use to test pages and other non-production uses.

As an example, to set a page as IE7 Emulation mode, enter the following between the HEAD tags, before any tags other than TITLE or META:

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

As another example, to set your page to render in Quirks mode for Windows Internet Explorer 8, enter the following between the HEAD tags, before any tags other than TITLE or META:

<meta http-equiv="X-UA-Compatible" content="IE=5"/>

This example specifies version compatibility at the site level for Internet Information Services (IIS) 7.0, setting to EmulateIE7 mode in the Web.config file:

XML

<?xml version="1.0" encoding="utf-8"?>
<configuration>
   <system.webServer>
      <httpProtocol>
         <customHeaders>
            <clear />
            <add name="X-UA-Compatible" value="IE=EmulateIE7" />
         </customHeaders>
      </httpProtocol>
   </system.webServer>
</configuration>

HTML Standard Compliance

Windows Internet Explorer 8 supports the HTML 4.01 Specification more closely than any previous version and supports features of the HTML 5 Specification. Some features were added and others were changed in order to better support the behavior expected by the standard. These changes make it easier to create Web sites that behave consistently when viewed with different browsers. Understanding these changes can help you create sites that display and function consistently, regardless of the browser used to view them.

Changes for HTML compliance include automatic closing of P elements, using OBJECT elements to display images, and improved Object Fallback.

CSS Standard Compliance

Windows Internet Explorer 8 is the most Cascading Style Sheets (CSS) compliant release yet, including full support for CSS level 2.1 and support for popular features of CSS level 3.0. There are many CSS improvements in Windows Internet Explorer 8, including Data URI, Floats, Printing, and more that let you layout your content as you wish, while maintaining compatibility with industry standards.