Can some explain this?

[Paul]

I saw this used as part of meta tags and wonder what exactly this does and if there is benefit to using it and if so.. what needs to be done to use it?

<META HTTP-EQUIV="Last-Modified" CONTENT="Wed Mar 24, 1999 08:04:46 AM EST">

<META HTTP-EQUIV="Expires" CONTENT="Tue Mar 23, 1999 08:04:46 AM EST">

Thanks...
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Paul

[Deb]

The expires tag I know...
This tells the browser if the doc is expired to initiate a new network request for the page.

Last Modified I'm not so sure on the specs for that one... What it means is obvious. But whether or not it does anything, I'm not sure.

Deb
p.s. for the heck of it, check out this page http://searchenginewatch.internet.com/resources/metasuits.html it shows many of the lawsuits that have occurred due to meta tags... *sigh* ya gotsta be careful here too.

[Justin]

Last modified is used because most browsers cache content. When the browser sends a request for a page, it tells the server the Last Modified date of the copy in it's cache, and the server will either return a new copy if there is one or a 304 - Not Modified, telling the browser to use the cached page.

In theory this should work perfect. But the Expires date throws in another tangent - it expired the day before it was created / modified, telling the browser to always reload the page.

This is fine for things like the UBB, where you always want the most current copy, but a lot of people use that so the user will always see new banners, etc http://www.aota.net/ubb/frown.gif In reality, I think all these dates are just ignored and pages are reloaded anyway.

In a perfect virtual world, you wouldn't use META tags for this. The same info is contained in the HTTP headers - but I *think* the META tag overrides the headers (as far as the browser is concerned). So we end up reloading a page and it's graphics every single time we visit the page even if it's exactly the same as it was before.

The other problem with using false dates for stuff like that is that ISP's that cache content totally ignore the dates, caching everything. Meaning that, since most pages use false Last Modified dates, the ISP assumes that every page does so it just says "Yeah, right. It wasn't modified. You're lying." and sends the cached page anyway.

This is what happens when people don't follow rules - that's why you can update your site and not see the results for a while. If things worked the way they should, if you update a page, the ISP and browser both would say "Ooh, it's been updated! Let's download it and flush the cache!". But that just doesn't happen.

Also, more and more content on the internet today is dynamic, like UBB's and search engines, where you *need* to know if it's been modified for real or not. The UBB, when it recreates the HTML files, puts the Last Modified date to sometime in the future (I think), where it should just tell you when it was really modified.

Geez - I didn't know I had so much to say about that! Well, there's my input for the day http://www.aota.net/ubb/biggrin.gif


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Justin Nelson
FutureQuest Tech Support

[Paul]

Ok.. thanks you two http://www.aota.net/ubb/smile.gif

So I guess if I read you right.. this is really unneeded and will do nothing toward moving up the food chain in the search engines?

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Paul

[Justin]

I would remove at least the Expires part - search engines don't like to index dynamic content, as it would never be accurate. If you tell it your page has expired already, then it has no need to index the page.

I suppose it is useful if you had a site dedicated to a christmas event, where you'd say it expires after 12-25-99, telling search engines to no longer index it after that date - but I think they will just not index them at all, figuring it's a waste of time and resources.

Either way, telling them that it has already expired is a bad idea...


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Justin Nelson
FutureQuest Tech Support

[auteur]

If I were you I'd remove both of them. The only meta tags you really need that will help you are:

<meta name="description" content="ENTER DESCRIPTION HERE">

<meta name="keywords" content="ENTER KEYWORDS HERE">



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Elizabeth M. Miller
Getting You the Attention You Deserve!
www.123marketing.com (http://www.123marketing.com)

[Paul]

auteur:

Thanks.. I don't have them on my pages..
I was just curious as to what benefit (if any) there is to using them.

A site that I keep an eye on uses them and they seem to place high in the rankings consistantly.