Internet Explorer May Not Use Images Stored in Local Cache

ID: Q217196

The information in this article applies to:

Microsoft Internet Explorer versions 4.01, 4.01 Service Pack 1 for Windows 95
Microsoft Internet Explorer version 4 for Windows 98
Microsoft Internet Explorer versions 4.01, 4.01 Service Pack 1 for Windows NT 4.0
Microsoft Windows 98

SYMPTOMS

You may notice that Internet Explorer seems to use its local cache differently when you view a Web page that uses frame sets than when you view a Web page that does not use frame sets. This behavior occurs when the frames consist of .asp pages, not .htm pages.

CAUSE

This behavior occurs because .asp pages are dynamic in nature and the content can change depending on the request. Even though Internet Explorer caches these images internally, Internet Explorer does not send an "If-Modified-Since" header in the image request ("GET") to the server. Therefore, every request causes the Web server to return the image to Internet Explorer, instead of Internet Explorer using a local copy from the local cache.

RESOLUTION

A supported fix that corrects this problem is now available from Microsoft, but it has not been fully regression tested and should be applied only to systems experiencing this specific problem. If you are not severely affected by this specific problem, Microsoft recommends that you wait for the next service pack that contains this fix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information on support costs, please go to the following address on the World Wide Web:

http://www.microsoft.com/support/supportnet/overview/overview.asp


   Date     Time    Size      File name   Platform
   -----------------------------------------------------
   2/15/99  2:19pm  2,630 KB  Mshtml.dll  Windows 95/98
   2/15/99  2:17pm  2,360 KB  Mshtml.dll  Windows NT 4.0

NOTE: Due to file dependencies, the most recent hotfix or feature that contains the above files may also contain additional files.

The design change in this resolution adds the "If-Modified-Since" header to any image request that uses .asp frames so that the Web server can respond with a "304 Not Modified" response to the image request. Internet Explorer then uses the local copy of the image if the image has already been cached and the image has not changed.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

Additional query words: framesets

Keywords : kbenv msiew95 msient win98
Version : WINDOWS:4,4.01,4.01 Service Pack 1
Platform : WINDOWS
Issue type : kbprb