Thank you for your comments about servers, server headings, proxies,
and user agent settings. However, my questions were (1) whether anyone
knows of software to slow down a broadband connection, and (2) how to
examine the contents of the rather opaque cache directories of a few
specific browsers (see my original query below).
Anybody know?
Thanks,
San
Lawrence San wrote:
[color=blue]
> I'm trying to test some simple JavaScript meant to speed up the display
> of my Web pages for readers using modems, but I have a fast DSL
> connection and I'm having trouble visualizing how effective the code
> is. Does anybody know of software that will simulate modem speed over a
> DSL connection -- i.e., temporarily slow down the speed of my
> connection, or the speed at which the browser uses the connection? (I
> author on a Mac but test on a PC -- I'm mostly interested in slowing
> down IE6 on Windows since that's what most people use.) I've searched
> but could not find such software. (I don't have a real 56K modem that
> can be used for this purpose.)
>
> My second question involves actually looking at the list of files that
> have loaded into the browser's cache. Windows IE6 seems to be the only
> one of my test browsers that lets me do this. Mac IE5 puts all the
> cache files into one big file that's opaque to me; Windows Netscape 6
> loads them as separate files, but renames the cache files to gibberish
> that I can't decipher.
>
> Is there a way to actually see what files are getting cached in these
> other browsers? Am I missing something?
>
> Thanks much,
> San[/color]
Grant Wagner <gwagner@agricoreunited.com> wrote:
[color=blue]
> What gets cached is a combination of server headers, intervening proxies
> and client user agent settings. You can only control the server headers to
> ensure that .js files are not configured to send "Expires: ...",
> "Cache-control: ... " or "Pragma: no-cache" headers (or if the server is
> sending Cache-control: headers, they are correct) <url:
>
http://www.mnot.net/cache_docs/#CONTROL />. My guess is that your server is
> configured correctly, it would take explicit action on the part of the Web
> server administrator to change those settings.
>
> You have no control over what any proxies between your server and the
> client might do, so I won't bother discussing it (although you *can*
> control some proxies to some extent with appropriate Cache-control: server
> headers).
>
> That leaves client user agent cache settings, which you also have NO
> control over. However, as long as the user has left the user agent
> (browser) configured as installed, the browser will be caching any files
> you send it.
>
> IE: Tools -> Internet Options -> General tab -> Settings -> Automatically
> Netscape 4: Edit -> Preferences -> Advanced -> Cache -> Once per session
> Firefox: No internal setting to control caching, but there are Extensions
> that can provide this functionality. From my use of this browser, it's
> obvious to me it refreshes the local cached copy when it detects the server
> copy is out of date.
> Mozilla 1.6: Edit -> Preferences -> Advanced -> Cache -> When the page is
> out of date
> Opera 7.5: Tools -> Preferences -> Network -> History and cache -> Check
> documents, Check images, Check other (which is the dopiest way to handle
> caching I've ever seen, but whatever)
> etc
> etc
> etc
>
> As you can see, and as I said, all you can control is the server. Ensure it
> is configured correctly. After that, caching behaviour will be the combined
> result of any proxies the page has to pass through and the client's user
> agent cache settings. If the user has their user agent configured
> correctly, it will cache, if they don't, it won't.
>
> --
> | Grant Wagner <gwagner@agricoreunited.com>
>
> * Client-side Javascript and Netscape 4 DOM Reference available at:
> *
>
>
http://devedge.netscape.com/library/...reference/fram
> es.html
>
> * Internet Explorer DOM Reference available at:
> *
>
>
http://msdn.microsoft.com/workshop/a...reference_entr
> y.asp
>
> * Netscape 6/7 DOM Reference available at:
> *
http://www.mozilla.org/docs/dom/domref/
> * Tips for upgrading JavaScript for Netscape 7 / Mozilla
> *
http://www.mozilla.org/docs/web-deve...upgrade_2.html
>
>[/color]
--
Lawrence San
Cartoon Stories for Thoughtful People:
<http://www.sanstudio.com>
email:
san@sanstudio.com 
