: When opening a local HTML file, how do I ensure I get the content not a cached version? I have an issue where the newest content of a local HTML file is sometimes not displayed. Instead,

@Harper822

To ensure content isn't cached, use no-store and must-revalidate in addition to the attributes you suggest. i.e.:

<meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate">
<meta http-equiv="Pragma" content="no-cache">
<meta http-equiv="Expires" content="0">


An explanation of those terms, from Mark Nottingham's Caching Tutorial (also see the official spec):


no-cache — forces caches to submit the request to the origin server for validation before releasing a cached copy, every time. This is useful to assure that authentication is respected (in combination with public), or to maintain rigid freshness, without sacrificing all of the benefits of caching.
no-store — instructs caches not to keep a copy of the representation under any conditions.
must-revalidate — tells caches that they must obey any freshness information you give them about a representation. HTTP allows caches to serve stale representations under special conditions; by specifying this header, you’re telling the cache that you want it to strictly follow your rules.


Reading these descriptions, you might think that including 'no-store' alone might be enough, but it's best to use all three in cases where you hope to ensure that no caching at all takes place.

You can simply set the Expires header to '0' to denote that it has expired. You need not use a full date and time.

The Pragma header is not used by modern (HTTP/1.1) caches, but W3C recommend that you include both Cache-Control and Pragma because older (HTTP/1.0) caching mechanisms don't support Cache-Control.

It's better to attempt to control caching with headers, and the above should work for all browsers. (The JavaScript you posted reloads the page, but this alone will not necessarily force a fresh copy of the content to be fetched.)

Vote Up Vote Down