BUG: Script Errors with Cache-Control:no-cache HTTP Header and HTTP Compression (327286)

SYMPTOMS

If you read Web pages from a site, an HTML page may be incomplete, or you may receive script error messages such as the following in Microsoft Internet Explorer (Programming) version 6.0:

Object doesn't support this property or method

-or-

'(object reference)' is null or not an object

It is also possible that an HTML page may be incomplete.
This occurs when you read Web pages from a site that uses all the following:

Script in external files, for example, JScript (.js) files
Frames and script inside the frames that refers to variables or to methods that are defined in other frames
HTTP compression to compress the HTML and the script files
HTTP headers that prevent the browser from caching the pages

The symptoms of this problem typically occur inconsistently and may appear random. Sometimes the error messages may appear when you first load the site. At other times the error messages may appear when you refresh the page.

WORKAROUND

To work around this problem, you can do either of the following:

If you use a Cache-Control: no-cache HTTP header to prevent the files from caching, remove that header. In some situations, if you substitute an Expires HTTP header, you do not trigger the problem.

-or-
Do not enable HTTP compression for the script files.

REFERENCES

For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:

234067 HOWTO: Prevent Caching in Internet Explorer

255801 How to Determine if HTTP Compression Is in Use

For more information about developing Web-based solutions for Microsoft Internet Explorer, visit the following Microsoft Web sites:

http://msdn.microsoft.com/ie/

http://support.microsoft.com/iep