This article describes how to install and use Compatibility mode with
Internet Explorer 5 or 5.5. You can use Compatibility mode to run an Internet
Explorer 4-compatible browser "side-by-side" with Internet Explorer 5 or 5.5.
The following topics are discussed:
- Purpose of Compatibility mode
- How to download or install Compatibility mode
- How to use Compatibility mode
- How to identify Compatibility mode
Purpose of Compatibility Mode
Some Web content can be affected by changes to the HTML parsing engine or
object (scripting) model incorporated into new versions of Internet
Explorer. For this reason, Web page authors or developers need to test
their content with each version of Internet Explorer for which their
content is designed. Prior to Internet Explorer 5, testing Web site
compatibility with various versions of Internet Explorer required multiple
computers or dual-boot configurations. With Compatibility mode, you can
run an Internet Explorer 4-compatible browser side-by-side with Internet
Explorer 5 or 5.5. Compatibility mode is designed for testing HTML parsing and
script issues and is not intended to be used as a primary Web browser.
How to Download or Install Compatibility Mode
To download or install Compatibility mode, use the following steps:
- Start the Internet Explorer 5 Setup program or the Internet Explorer 5.5 Setup program, click I Accept The
Agreement, click Next, click Customize Your Installation, and then
- In the Components Options dialog box, click Advanced, and then click to
select the Compatibility check box. If you want to download (instead of
install) Compatibility mode, click to select the Download Only check
- Click OK, and then click Next to continue the Setup program.
: If you are not running Internet Explorer 4 when you follow the above
steps, you cannot select the Compatibility option. You can download or
install Compatibility mode only when you upgrade or downloade from
Internet Explorer 4. Compatibility mode is not supported for versions of
Internet Explorer prior to 4.0. If you are already running Internet
Explorer 5 or 5.5 and you need to download or install Compatibility Mode,
remove Internet Explorer 5 or 5.5 before following the above steps.
For additional information about removing Internet Explorer 5, click the following article number to view the article in the Microsoft Knowledge Base:
How to uninstall Internet Explorer 5 Beta
How to Use Compatibility Mode
To use Internet Explorer 4 to browse the Internet after installing
Internet Explorer 5 or 5.5, click Start, point to Programs, point to Internet
Explorer, and then click "Previous Internet Explorer Ver. 4."
: When you install Internet Explorer 5 or 5.5 with the Compatibility option,
Internet Explorer 5 or 5.5 and Internet Explorer 4 share the same Internet
options. You may not be able to change all settings for the browser while
using this mode. When you are using Compatibility mode, you should change
Internet options through Control Panel, not by clicking Internet Options
on the View menu in Internet Explorer.
How to Identify Compatibility Mode
To determine if you are using the Compatibility-mode browser, use the
- In Internet Explorer, click About Internet Explorer on the Help menu.
- If the version is reported as "Side-by-Side Mode," you are using
: Compatibility mode can be identified by Web developers using the
"compat" string, which is added to the User Agent for the Compatibility-
mode browser. For example, the User Agent for Compatibility mode in
Windows 98 is:
Mozilla/4.0 (compatible; MSIE 4.01; Windows 98; compat)