+>action
+ configuration files</A
+>, are explained in depth below.</P
+><P
+> Actions are specified in <SPAN
+CLASS="APPLICATION"
+>Privoxy's</SPAN
+> configuration,
+ followed by one or more URLs to which the action should apply. URLs
+ can actually be URL type <A
+HREF="actions-file.html#AF-PATTERNS"
+>patterns</A
+> that use
+ wildcards so they can apply potentially to a range of similar URLs. The
+ actions, together with the URL patterns are called a section.</P
+><P
+> When you connect to a website, the full URL will either match one or more
+ of the sections as defined in <SPAN
+CLASS="APPLICATION"
+>Privoxy's</SPAN
+> configuration,
+ or not. If so, then <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> will perform the
+ respective actions. If not, then nothing special happens. Furthermore, web
+ pages may contain embedded, secondary URLs that your web browser will
+ use to load additional components of the page, as it parses the
+ original page's HTML content. An ad image for instance, is just an URL
+ embedded in the page somewhere. The image itself may be on the same server,
+ or a server somewhere else on the Internet. Complex web pages will have many
+ such embedded URLs. <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> can deal with each URL individually, so, for
+ instance, the main page text is not touched, but images from such-and-such
+ server are blocked.</P
+><P
+> The most important actions for basic ad blocking are: <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#BLOCK"
+>block</A
+></TT
+>, <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#HANDLE-AS-IMAGE"
+>handle-as-image</A
+></TT
+>,
+ <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#HANDLE-AS-EMPTY-DOCUMENT"
+>handle-as-empty-document</A
+></TT
+>,and
+ <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#SET-IMAGE-BLOCKER"
+>set-image-blocker</A
+></TT
+>:</P
+><P
+> <P
+></P
+><UL
+><LI
+><P
+> <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#BLOCK"
+>block</A
+></TT
+> - this is perhaps
+ the single most used action, and is particularly important for ad blocking.
+ This action stops any contact between your browser and any URL patterns
+ that match this action's configuration. It can be used for blocking ads,
+ but also anything that is determined to be unwanted. By itself, it simply
+ stops any communication with the remote server and sends
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+>'s own built-in BLOCKED page instead to
+ let you now what has happened (with some exceptions, see below).
+ </P
+></LI
+><LI
+><P
+> <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#HANDLE-AS-IMAGE"
+>handle-as-image</A
+></TT
+> -
+ tells <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> to treat this URL as an image.
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+>'s default configuration already does this
+ for all common image types (e.g. GIF), but there are many situations where this
+ is not so easy to determine. So we'll force it in these cases. This is particularly
+ important for ad blocking, since only if we know that it's an image of
+ some kind, can we replace it with an image of our choosing, instead of the
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> BLOCKED page (which would only result in
+ a <SPAN
+CLASS="QUOTE"
+>"broken image"</SPAN
+> icon). There are some limitations to this
+ though. For instance, you can't just brute-force an image substitution for
+ an entire HTML page in most situations.
+ </P
+></LI
+><LI
+><P
+> <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#HANDLE-AS-EMPTY-DOCUMENT"
+>handle-as-empty-document</A
+></TT
+> -
+ sends an empty document instead of <SPAN
+CLASS="APPLICATION"
+>Privoxy's</SPAN
+>
+ normal BLOCKED HTML page. This is useful for file types that are neither
+ HTML nor images, such as blocking JavaScript files.
+ </P
+></LI
+><LI
+><P
+> <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#SET-IMAGE-BLOCKER"
+>set-image-blocker</A
+></TT
+> - tells
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> what to display in place of an ad image that
+ has hit a block rule. For this to come into play, the URL must match a
+ <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#BLOCK"
+>block</A
+></TT
+> action somewhere in the
+ configuration, <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>and</I
+></SPAN
+>, it must also match an
+ <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#HANDLE-AS-IMAGE"
+>handle-as-image</A
+></TT
+> action.
+ </P
+><P
+> The configuration options on what to display instead of the ad are:
+ </P
+><P
+></P
+><TABLE
+BORDER="0"
+><TBODY
+><TR
+><TD
+> <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>pattern</I
+></SPAN
+> - a checkerboard pattern, so that an ad
+ replacement is obvious. This is the default.
+ </TD
+></TR
+></TBODY
+></TABLE
+><P
+></P
+><P
+></P
+><TABLE
+BORDER="0"
+><TBODY
+><TR
+><TD
+> <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>blank</I
+></SPAN
+> - A very small empty GIF image is displayed.
+ This is the so-called <SPAN
+CLASS="QUOTE"
+>"invisible"</SPAN
+> configuration option.
+ </TD
+></TR
+></TBODY
+></TABLE
+><P
+></P
+><P
+></P
+><TABLE
+BORDER="0"
+><TBODY
+><TR
+><TD
+> <SPAN
+CLASS="emphasis"
+><I
+CLASS="EMPHASIS"
+>http://<URL></I
+></SPAN
+> - A redirect to any image anywhere
+ of the user's choosing (advanced usage).
+ </TD
+></TR
+></TBODY
+></TABLE
+><P
+></P
+></LI
+></UL
+></P
+><P
+> Advanced users will eventually want to explore <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+>
+ <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#FILTER"
+>filters</A
+></TT
+> as well. Filters
+ are very different from <TT
+CLASS="LITERAL"
+><A
+HREF="actions-file.html#BLOCK"
+>blocks</A
+></TT
+>.
+ A <SPAN
+CLASS="QUOTE"
+>"block"</SPAN
+> blocks a site, page, or unwanted contented. Filters
+ are a way of filtering or modifying what is actually on the page. An example
+ filter usage: a text replacement of <SPAN
+CLASS="QUOTE"
+>"no-no"</SPAN
+> for
+ <SPAN
+CLASS="QUOTE"
+>"nasty-word"</SPAN
+>. That is a very simple example. This process can be
+ used for ad blocking, but it is more in the realm of advanced usage and has
+ some pitfalls to be wary off.</P
+><P
+> The quickest way to adjust any of these settings is with your browser through
+ the special <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> editor at <A
+HREF="http://config.privoxy.org/show-status"
+TARGET="_top"
+>http://config.privoxy.org/show-status</A
+>
+ (shortcut: <A
+HREF="http://p.p/"
+TARGET="_top"
+>http://p.p/show-status</A
+>). This
+ is an internal page, and does not require Internet access.</P
+><P
+> Note that as of <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> 3.0.7 beta the
+ action editor is disabled by default. Check the
+ <A
+HREF="config.html#ENABLE-EDIT-ACTIONS"
+TARGET="_top"
+>enable-edit-actions
+ section in the configuration file</A
+> to learn why and in which
+ cases it's safe to enable again.</P
+><P
+> If you decided to enable the action editor, select the appropriate
+ <SPAN
+CLASS="QUOTE"
+>"actions"</SPAN
+> file, and click
+ <SPAN
+CLASS="QUOTE"
+>"<SPAN
+CLASS="GUIBUTTON"
+>Edit</SPAN
+>"</SPAN
+>. It is best to put personal or
+ local preferences in <TT
+CLASS="FILENAME"
+>user.action</TT
+> since this is not
+ meant to be overwritten during upgrades, and will over-ride the settings in
+ other files. Here you can insert new <SPAN
+CLASS="QUOTE"
+>"actions"</SPAN
+>, and URLs for ad
+ blocking or other purposes, and make other adjustments to the configuration.
+ <SPAN
+CLASS="APPLICATION"
+>Privoxy</SPAN
+> will detect these changes automatically.</P
+><P
+> A quick and simple step by step example:</P
+><P
+> <P
+></P
+><UL
+><LI
+><P
+> Right click on the ad image to be blocked, then select
+ <SPAN
+CLASS="QUOTE"
+>"<SPAN
+CLASS="GUIMENUITEM"
+>Copy Link Location</SPAN
+>"</SPAN
+> from the
+ pop-up menu.
+ </P
+></LI
+><LI
+><P
+> Set your browser to
+ <A
+HREF="http://config.privoxy.org/show-status"
+TARGET="_top"
+>http://config.privoxy.org/show-status</A
+>
+ </P
+></LI
+><LI
+><P
+> Find <TT