"Pragma: No-cache" Tag May Not Prevent Page from Being Cached

Prohlášení o odmítnutí odpovědnosti pro už nepodporovaný obsah KB

Tento článek byl napsán pro produkty, ke kterým již Microsoft nadále nenabízí podporu. Článek je tedy poskytován „tak, jak je“ a nebude už nadále aktualizován.

Symptoms

When you use the <HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE"> metatag in the header section at the beginning of an HTML Web page, the Web page may still be cached in the Temporary Internet Files folder.

Cause

A page that Internet Explorer is browsing is not cached until half of the 64 KB buffer is filled. Usually, metatags are inserted in the header section of an HTML document, which appears at the beginning of the document. When the HTML code is parsed, it is read from top to bottom. When the <HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE"> metatag is read, Internet Explorer looks for the existence of the page in cache at that exact moment. If it is there, it is removed.

Resolution

To properly prevent the Web page from appearing in the cache, place another header section at the end of the HTML document. For example:

<HTML>

<HEAD>

<META HTTP-EQUIV="REFRESH" CONTENT="5">
<TITLE> Pragma No-cache </TITLE>
</HEAD>

<BODY>

This is an example of where to place the second header section<br>
so that the "Pragama, No-Cache" metatag will work as it is supposed to.<br>

</BODY>

<HEAD>

<META HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE">
</HEAD>

</HTML>

More Information

Note that the <HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE"> metatag does not work with Internet Explorer 5. For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

234067 HOWTO: Prevent Caching in Internet Explorer
Vlastnosti

ID článku: 222064 - Poslední kontrola: 22. 6. 2014 - Revize: 1

Váš názor