Re: Re: selective blocking flashs

Micha <[email protected]>
Newsgroups gmane.network.wwwoffle.user
Message-ID <20041217200101.7814fd78@puck>
Hi Andrew, hi galeon folks,

So javascript can circumvent my proxy ? What else can js do then ? Download more code, which also 
downloads more code which downloads more stuff ? Keeping my machine busy with things i don't have the slightest clue about ?
I can't imagine this is true ! At least a browser must be controllable, there should be settings.
I remember there were a lot of settings in iexplorer last time i configured and used one (but it's a
_long_ while since ;)
With galeon, for example, i can set some few limits to what js can do. I didn't discover a way to say
don't download flashs from this site yet. But I always believed i can do that and more with a proxy.

amb-Uxr6IM1mbv2TY6FTCsQk+9Bc4/[email protected] (Andrew M. Bishop): 
> The sequence of events is this.
> 
> 1) The server sends HTML including Javascript.
> 2) WWWOFFLE is here and hides any flash animations but leaves Javascript unchanged.
> 3) The browser runs the Javascript which writes out some extra HTML into the page.
> 4) The browser displays the modified HTML which includes the flash animation object tags that the Javascript wrote.
> 5) The browser gets the flash animation and displays it.
> 
> Here is an example piece of Javascript that shows how it works (but for images and not flash).
>
> -------------------- example.html --------------------
> <script LANGUAGE="JAVASCRIPT">
> <!--
> now = new Date();
> tail = now.getTime();
> document.write("<IMG SRC='//images-aud.slashdot.org/pc.gif?l,");
> document.write(tail);
> document.write("' WIDTH=1 HEIGHT=1 BORDER=0 ALT=' '>");
> //-->
> </SCRIPT>
> -------------------- example.html --------------------
> 
> When this script is run you will end up with some extra HTML that the browser will see in step (4)
> but that WWWOFFLE could not see in step (2).  The extra image in this case will be loaded by an HTML
> tag that looks like shown below but with $$$ replaced by the current time:
> 
> <IMG SRC='//images-aud.slashdot.org/pc.gif?l,$$$' WIDTH=1 HEIGHT=1 BORDER=0 ALT=' '>
>
> If WWWOFFLE contained a Javascript interpreter that gave exactly the same result as the Javascript
> interpreter in the browser then there would be a chance.  It would have to detect that the Javascript
> changes the HTML in the page and then delete that part of the script. I don't think that this is practical though.
> -- 
> Andrew.
> ----------------------------------------------------------------------
> Andrew M. Bishop                             amb-Uxr6IM1mbv2TY6FTCsQk+9Bc4/[email protected]
>                                       http://www.gedanken.demon.co.uk/

ok, it's just this way, granted. The browser interpreting the javascripted html page will send download requests.
Why do those requests ignore the proxy then ? Did i configure galeon to work with a proxy and then it's not
used in some cases ? Couldn't that be changed at least by the developers (hi there !) ? 

greets, micha
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