Firefox extension for evaluating links and linked content. Download
Requirements, License Information
Colors - explanation
Evaluator with special "Link Evaluator-aware" content online
Link Evaluator is a Firefox extension designed to help users evaluate
the availability of online resources linked to from a given Web
page. When started, it automatically follows all links on
the current page, and assesses the
responses of each URL (link).
Link Evaluator examines both the
HTTP status code and
the page contents returned by each URL, and attempts to
between various results such as:
- broken links (404)
- network time-outs
- authentication failure, and
- "incorrect" content for the given
After each link is checked, it is highlighted with a color based on the
relative success of the result: green for fully successful, shades of
yellow for partly successful, and red for unsuccessful.
Link Evaluator is capable of detecting "red-flag" and
"green-flag" phrases embedded in Web content specifically for checking
links, i.e. text that is likely to
indicate a Web page has been successfully reached or not. You can also
edit the sets of red- and green-flag phrases to be used.
You can also create special "Link Evaluator-aware" test pages in which
the test phrases for each resource are embedded right in the
HTML. For example, a library could create a page of test
links for its particular set of electronic resources, and then add test
phrases to the page, so that all the library's resources can be
accurately evaluated at any later point, by simply running Link
Evaluator on this test page.
You can also use Link Evaluator to
test all of your bookmarked links at once (new feature added January
Technical Requirements, License Information
Link Evaluator is designed for Mozilla
version 1.5 and later.
The extension and accompanying
(c) Copyright 2006 OCLC Online Computer Library Center, Inc.
Licensed under the Apache License, Version 2.0 (the
"License"); you may not use this material except in compliance with the
License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or
agreed to in
writing, materials distributed under the License are distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
express or implied. See the License for the specific language governing
permissions and limitations under the License.
download the extension.
Note that your browser security settings may cause the download to be
blocked. In this case, you must edit your settings to allow
downloads from this site.
- If Firefox brings up an
installation prompt, click
If it asks you if you want to open or save the file, open the file with
Firefox as the application. Alternatively, you can save the file to
disk and drag it on to the Firefox window.
- Quit (exit) the browser, then
extension will then be installed.
Starting the Link Evaluator tool
First, point your browser to a Web page whose links you wish to
test. For example, you could use Link
Evaluator Examples Page.
Then, run Link Evaluator, using any of these three methods:
- Go to your browser's "Tools" menu,
select "Link Evaluator", and
"Evaluate Links" from the sub-menu;
- On any Web page, right-click
anywhere on the page
(or for Mac users, control-click), and select "Evaluate Links" from the
context menu; or
- Select "Start" in the Monitor
section of the Link
Evaluator Control Panel (see below).
Using Link Evaluator to test your
You can test all of your bookmarked pages at once with Link
Evaluator. To do this, go to your browser's "Tools" menu, select
"Link Evaluator", and then select "Evaluate bookmarks in a new tab"
from the sub-menu.
Opening the Link Evaluator Control
The Control Panel is used to change
results, and as an alternate way to start/stop Link
Evaluator. (note: this
is not the same as the the Windows XP Control Panel tool reached from
the Windows Start menu).
To open Control Panel, either
- select from your browser menu
"Tools > Link
Evaluator > Link Evaluator... "; or
- right-click anywhere on a Web page
Mac users), and select "Link Evaluator..." from the context menu.
The popup panel contains the following four sections:
- "Red/green-flag phrases",
the first section is for customization
(see next sections),
the next tab (monitor) can be used to start and stop the link testing
and to see the log of the tests.
Viewing Results and Halting Link Evaluator:
The results of page evaluation, during or after Link Evaluator runs,
can be viewed in the Monitor area of the Control Panel.
Also, a test progress indicator appears in the right side of your
browser's status bar while Link Evaluator is running. (note that the
status bar may not display if it is turned off in your browser. Go to
View > Status Bar in your browser menu to turn on).
You can halt Link Evaluator while it is running by double-clicking on
this status indicator.
Also, if you roll over (mouse over) the link, text will appear noting
the HTTP status found for that link, and also any "green-flag" or
"red-flag" phrases found in the page content. (see Editing the Red/Green-flag
for more about flag phrases).
Link Evaluator examines the content returned by each URL for the
presence of certain "green-flag" and "red-flag" phrases. These
are words or phrases which are known to often indicate successful or
failed links: for example, "Table of contents" or "Not
You can view, edit or add to the set of phrases used, by going to the
"Red/green-flag phrases" area of the Control
Panel. There are two colored sections there - red and green.
In each of these sections there is a default set of phrases, with
each line of text representing a unique phrase. You can edit,
remove, or add to the set of phrases. Select "Activate" to
use them the next time you perform test with Link Evaluator.. At
any time during the edit process, you can reload the active set of
selecting "Read active."
The user can create and store named sets of red- and green-flag
phrases, i.e. test profiles. There is one built-in profile (more will
later). Each profile contains a set of red-flag and a set of green-flag
A drop-down box in the "Red/green-flag phrases" area of the Control
the currently available profiles. Choosing "New profile" would activate
a prompt asking to give it
a name. Then you may edit the content of the red and green boxes inside
There is a modify/save button,
that would save the current content of the red and green boxes under
the currently chosen profile name.
After editing or reloading a phrase set, you must click on "Activate"
for this set to be used the next time you run Link Evaluator.
Note that the Red-flag set and the Green-flag set each have their own
"Activate" buttons, you must click on both to activate after loading a
Link Background Colors - explanation
After a link is tested, Link Evaluator
background color behind the link to indicate the "score", or degree of
success, found during the evaluation.
The link background will turn RED If the link failed, or
if mostly red-flag phrases were found in the response. It will turn
GREEN if the link returned an "OK" status code and green-flag
If a mixture of results is found, then the link background will be
given a color somewhere between red and green on the RGB scale, ranging
reddish-yellow (orange), to yellow, to green-yellow.
Using Link Evaluator with special "Link Evaluator-aware" content online
Link Evaluator is capable of detecting red- and green-flag phrases that
have been embedded in special Web content for testing purposes. This
"Link Evaluator-aware" content can contain flag phrases that are
to be applied only to specific links or ranges of links.
So, you can create smart test pages on which you add words or
phrases which you know to be present
on successfully retrieved pages for a given URL or
group of URLs.
To create such content, simply place DIV elements into your HTML
content above the links to be tested, describing the flag phrase to be
For example, to set a red-flag phrase of "access denied" and a
green-flag phrase of "billion items" for the WorldCat.org web site:
<div class="linkval_FP_red" title="access denied">
<div class="linkval_FP_green" title="billion items">
See the Link
Evaluator Examples Page for more information and example test