User Manual

ProxySG Content Policy Language Guide
248
define active_content
Defines rules for removing or replacing active content in HTML or ASX documents. This definition
takes effect only if it is invoked by a
transform action in a define action definition block, and that
block is in turn enabled an
action( ) property as a result of policy evaluation.
Active content transformation acts on the following four HTML elements in documents:
<applet>,
<embed>, <object>, and <script>. In addition, a script transformation removes any JavaScript
content on the page. For each tag, the replacement can either be empty (thus deleting the tag and its
content) or new text that replaces the tag. Multiple tags can be transformed in a single active content
transformer. Pages served over an HTTPS tunneled connection are encrypted so the content cannot be
modified.
Note: Transformed content is not cached, in contrast with content that has been sent to a virus
scanning server. Therefore, a transformer can be safely triggered based on any condition,
including client identity and time of day.
Replaces:
transform active_content
Syntax
define active_content transformer_id
tag_replace HTML_tag_name << text_end_delimiter
[replacement_text]
text_end_delimiter
[tag_replace ...]
...
end
where:
•
transformer_id—A user-defined identifier for a transformer definition block. Used to invoke the
transformer using the
transform action in a define action definition block.
•
HTML_tag_name—The name of an HTML tag to be removed or replaced, as follows:
❐ applet—Operates on the <applet> element, which places a Java applet on a web page.
❐ embed—Operates on the <embed> element, which embeds an object, such as a multimedia file,
on a web page.
❐ object—Operates on the <object> element, which places an object, such as an applet or
media file, on a web page.
❐ script—Operates on the <script> element, which adds a script to a web page. Also removes
any JavaScript entities, strings, or events that may appear on the page.
If the
tag_replace keyword is repeated within the body of the transformer, multiple HTML tags
can be removed or replaced.
•
text_end_delimiter—A user-defined token that does not appear in the replacement text and
does not use quotes or whitespace. The delimiter is defined on the first line, after the required
double angle brackets (
<<). All text that follows, up to the second use of the delimiter, is used as
the replacement text.
•
replacement_text—Either blank, to remove the specified tag, or new text (including HTML
tags) to replace the tag.