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seems to be quite popular with some major (i.e. large branded) companies in the UK. What is it for and why set it to something as ridiculous as 1997?
So, the aim on sites may be to stop visitors using a cache of pages.
[w3.org...]
HTML authors can put tags in a document’s <HEAD> section that describe its attributes. These meta tags are often used in the belief that they can mark a document as uncacheable, or expire it at a certain time.Meta tags are easy to use, but aren’t very effective. That’s because they’re only honored by a few browser caches (which actually read the HTML), not proxy caches (which almost never read the HTML in the document). While it may be tempting to put a Pragma: no-cache meta tag into a Web page, it won’t necessarily cause it to be kept fresh.
For asking robots to reindex the page, you've got revisit-after (however, it is not likely to have any effect nowadays).
No we don't.
Revisit-After META Tag
The myth continues in 2004
[webmasterworld.com...]
Note to self. I need to update the description of that topic to read...
The myth continues in 2006
The "expires" tells UAs that the content of the page expires at the given date and time, so caches should be updated by then. The reason it says 1997 can be because they wish the UAs to update the cache at every visit, or, more likely I suppose, it's just legacy code which hasn't been updated or removed.
It can also send an instruction to remove the page as it has expired and is no longer valid content. A misinterpretation of the standards possibly?
Anything to do with expiration should be handled at the server level using the proper HTTP Headers.
In this particular case, certain browsers may not keep a copy of the page in the browser cache, but the efect is limited.
7.4.4 Meta data
[w3.org...]
The http-equiv attribute can be used in place of the name attribute and has a special significance when documents are retrieved via the Hypertext Transfer Protocol (HTTP). HTTP servers may use the property name specified by the http-equiv attribute to create an [RFC822]-style header in the HTTP response. Please see the HTTP specification ([RFC2616]) for details on valid HTTP headers.
Remember, these are some of the top companies in the UK, I have to assume that they all have hired the top notch internet staff to run their websites. I doubt external SEO/Design firms are responsible for this sort of thing in this instance!
No we don't.
The link in mattur's post above is to one of the most detailed and authoritative sources on web caching - it's a very worthwhile read!
[edited by: encyclo at 4:20 pm (utc) on May 24, 2006]
[edit reason] fixed link ;) [/edit]
So basically that tag does not have a set rule/intent to it? All crawlers and/or browsers may treat it completely different to each other?
I would expect all crawlers to ignore it completely. Some browsers theoretically support it (IE5.5+, don't know about others) but cannot support it if there is a cache upstream that doesn't parse the HTML, only the HTTP headers (the browser won't cache the page but the upstream cache probably will).
Remember, these are some of the top companies in the UK, I have to assume that they all have hired the top notch internet staff to run their websites
That's a pretty big assumption ;)
What is the connection between that one, and [web-caching.com...]The Cacheability Engine and related docs were written by Mark Nottingham and are published on mnot.net. web-caching.com also hosts a copy (along with other related resources).
The latest revision of this document can always be obtained from [mnot.net...]
seems to be quite popular with some major (i.e. large branded) companies in the UK.
This would lead me to think that the "large" companies involved make some internal use of the meta tag.
This would lead me to think that the "large" companies involved make some internal use of the meta tag.
Go on. What use could you have for such a tag?
