The DomDocument Load Method Ignores Content Expiration

When you call the load method of the XML2.DOMDocument object to load an XML document through a script, Internet Explorer sends an "If-Modified-Since" header for the XML file.

The MSXML2.DomDocument load method relies on Urlmon to load the file. When it calls Urlmon, MSXML2.DomDocument sets the BINDF_RESYNCHRONIZE flag. This results in a conditional GET request being sent to the server if the data is already in the cache.

BINDF_RESYNCHRONIZE is used because of an Internet Explorer issue that causes undated documents to stay in the cache indefinitely. This issue has been fixed in Internet Explorer 5.5 Service Pack 2 and Internet Explorer 6. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

A supported hotfix is available from Microsoft. However, this hotfix is intended to correct only the problem that is described in this article. Apply this hotfix only to systems that are experiencing this specific problem. This hotfix might receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

If the hotfix is available for download, there is a "Hotfix download available" section at the top of this Knowledge Base article. If this section does not appear, contact Microsoft Customer Service and Support to obtain the hotfix.

Note If additional issues occur or if any troubleshooting is required, you might have to create a separate service request. The usual support costs will apply to additional support questions and issues that do not qualify for this specific hotfix. For a complete list of Microsoft Customer Service and Support telephone numbers or to create a separate service request, visit the following Microsoft Web site: Note The "Hotfix download available" form displays the languages for which the hotfix is available. If you do not see your language, it is because a hotfix is not available for that language. The English version of this fix should have the following file attributes or later:
After you install this hotfix, you can use a new property that is named ForcedResync with the default value set to True. You can do this to keep the current behavior (a conditional GET request) for existing programs. You must set this property to False to suppress resynchronization (to prevent XML from using BINDF_RESYNCHRONIZE). To do this, use this method: To avoid any problems when you set ForcedResync to False, documents must have expiration dates, or the client must be Internet Explorer 5.5 Service Pack 2 or Internet Explorer 6.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.

Note that installing this hotfix and setting the ForcedResync property to False solves one of the issues that is described in the following Microsoft Knowledge Base article: