In order to measure the code coverage of a page on
you must run
jscoverage to create a
jscoverage.html file on the
example.com server. You cannot use
to measure the code coverage of a page located on
(In fact, the current version of JSCoverage is slightly more restrictive
same directory as the
jscoverageprogram or the
First, note that the
jscoverage program and the
jscoverage-server program are mutually exclusive alternatives;
you must use one or the other, but not both. If you try to use both at the same time you will get strange results.
Which of the two programs you use is largely a matter of personal preference.
jscoverage-server program has some additional features,
such as the ability to store coverage reports to disk.
jscoverage program is the more mature of the two and is generally easier to use;
this program is recommended if you do not need any of the additional features of
Firefox 3 introduces new security restrictions on local files. Depending on the way your test suite is organized, this may cause problems for JSCoverage. (You may get the error "uncaught exception: Permission denied to get property Window._$jscoverage".) There are several workarounds:
Place your files on a web server instead of loading them from the file system. This is usually the simplest solution.
Organize your HTML files in your test suite in a flat directory structure. For example, suppose that you instrument your test suite with this command:
jscoverage src instrumented
If all your HTML files are located directly under the
src/ directory (i.e., not in a
src/), then you should not have any problems using Firefox 3.
Internet Explorer 6 seems to have problems with a
that has a query string with a slash in it.
As a workaround:
Place your files on a web server instead of loading them from the file system.
http: URLs work fine.)
Do not use a query string; enter your URL in the "URL" field in the "Browser" tab.
Rearrange your directory structure so that
ends up in the same directory as
you can use the URL
with no slash in the query string.
Use a different browser. (IE 7 seems to work.)
Certain browsers (e. g., Internet Explorer 6, Opera, Safari) have trouble changing the cursor. Try moving the mouse and your cursor should change back to normal.
See this discussion for more information.
With Internet Explorer 6 (I think I see a pattern here), garbage collection can cause performance problems. (More information here.)
It is necessary to run JSCoverage in inverted mode. You will have to modify JsUnit to launch JSCoverage.
See the directory
doc/example-jsunit for an example. It
contains a copy of JsUnit version 2.2alpha11, with the file
jsunit/app/main-data.html slightly modified to add a button
which launches JSCoverage. It also contains a simple unit test file
can instrument this example as follows:
jscoverage --no-instrument=jsunit doc/example-jsunit doc/instrumented-jsunit
You can then run the
test.html file in JsUnit's
The simplest way to do this is probably to copy the contents of
to the root of a web server and then access the URL
After the test suite has been run, click on the "Coverage report" button to get a coverage report.
Internet Explorer does
not use a proxy for URLs with host
The proxy will be used if you use your machine's actual IP
address or host name.
For example, if your IP address is
192.168.100.100, you can
access a URL like
Internet Explorer and it will work.
(Under Windows, you can get your machine's IP address with the