Instructions for Advanced Webmasters

 

 

Instructions for Advanced Webmasters

Keeping portions of your web page

If you are a webmaster and use a page monitoring service such as ChangeDetect, you will want to avoid false-positive reporting of web page changes.

False-positive reports are irrelevant ChangeDetect notifications sent to subscribers.  Some of your pages may have many small changes, use session keys, rotate graphics, display advertisement banners, show the current date or count page impressions/hits.

ChangeDetect will detect any of these minor changes and will therefore generate a page change notice to the web page subscriber.  In order to ignore this "active content" and to control change notification, enclose the relevant sections of your web page content with the "start" and "end" tags as follows:

   <!--ChangeDetect start keep-->

   <!--ChangeDetect end keep-->

The content between the "start" and "end" tags is filtered by the ChangeDetect monitor and checked for changes.

Keep tags are useful for extracting prime interest areas of HTML pages without the surrounding boilerplate.

Keep tags take priority over ignore tags (discussed below).  If you use keep tags, the ignore tags will not be processed.

Refer to the sample page for an illustration.

Update:  If you want to avoid false alarms completely and simplify your use of ChangeDetect, then add a "Last modified date" field to your web pages.  Then use the keep tags to enclose the "last modified date" field.

Webmasters, having trouble with "false-positive" web page change notifications, report this approach to be the most effective method to setting up a "monitor this page" form on their web pages.

Here is a good example leveraging the "Last modified date" field.

Remember:  Keep tags take priority over ignore tags (discussed below).  If you use keep tags, the ignore tags will not be processed.

Feel free to contact us with any especially troublesome web page monitors.  False-positive web page change notifications are very annoying for users so we will do our best to help you.

Ignoring portions of your web page (Option 1)

If you are a webmaster and use a page monitoring service such as ChangeDetect, you will want to avoid false-positive reporting of web page changes.

False-positive reports are irrelevant ChangeDetect notifications sent to subscribers.  Some of your pages may have many small changes, use session keys, rotate graphics, display ad banners, show the current date or count page impressions/hits.

ChangeDetect will detect any of these minor changes and will therefore generate a page change notice to the web page monitoring subscriber.  In order to ignore this "active content" and to control what types of changes ChangeDetect monitors, enclose the irrelevant sections of your web page content with the "start" and "end" tags as follows:

   <!--ChangeDetect start ignore-->

   <!--ChangeDetect end ignore-->

The content between the "start" and "end" tags is ignored by the ChangeDetect monitor.

This is useful for excluding boilerplate or otherwise unwanted portions of HTML documents.

Refer to the sample page for an illustration.

Feel free to contact us with any especially troublesome web page monitors.  False-positive web page change notifications are very annoying for users so we will do our best to help you.

Ignoring portions of your web page (Option 2)

[The following option is very rarely used and not recommended for most users.]

ChangeDetect ignores the "changedetect_suppress" query string and will strip it from the URL when communicating with visitors to your web page.  

So if you want to suppress active content on a page that changes with every session (like the current date and time), then pass the query string, changedetect_suppress=1 as a query string.  Then within your code, suppress all active content with an if-then statement so that ChangeDetect does not falsely detect changes to your pages just because some trivial data item (ie. current date, random image include) has changed.

Using this query string setting allows you to offer ChangeDetect monitoring services for your pages with active content.

Here is an example of this query string used:

    http://www.changedetect.com/?changedetect_suppress=1&now=True

The ChangeDetect chron job (script) will load "http://www.changedetect.com/?changedetect_suppress=1&now=True" to check the page, but the user will be notified and informed about "http://www.changedetect.com/?now=True".  The user sees the active content, but the script only monitors the static page details. 

You have to understand active content to fully appreciate the benefit of this feature.  But it is optional so if you do not understand it, then you probably do not need it.

Using ASP, PHP or Perl for Dynamic Page Generation

[The following option is not required for most users.]

You may use scripting language code like ASP, PHP or Perl to dynamically generate the name of the webpage you want to make available for monitoring.  

For Active Server Pages (ASP), you would put something similar to the following code in an include file and call it from any page you want to offer for monitoring:

<% webpage = Request.ServerVariables ("server_name") & Request.ServerVariables ("script_name") & "?" & Request.ServerVariables ("query_string") %>

You would replace "*** insert webpage here ***" in the form with:

<% =webpage %>