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</head>
<body>

<h1>JSCoverage user manual</h1>

<p>
JSCoverage is a tool used to measure code coverage in JavaScript
programs.
</p>

<p>
JSCoverage has two components:
</p>

<ol>
<li>An executable program which is used to add instrumentation to JavaScript code.
<li>A web application which is used to execute instrumented code and generate a
code coverage report.
</ol>

<h2>Installing JSCoverage</h2>

<p>
You can compile JSCoverage on GNU/Linux or Microsoft Windows, using GCC. On
Windows you will require <a href="http://cygwin.com/">Cygwin</a> or <a
href="http://mingw.org/">MinGW/MSYS</a>.
</p>

<p>
You can extract and compile the code with the following commands:
</p>

<pre>
tar jxvf jscoverage-0.3.tar.bz2
cd jscoverage-0.3/
./configure
make
</pre>

<p>
This will create the <code>jscoverage</code> executable (<code>jscoverage.exe</code> on Windows).
You can install the executable in <code>/usr/local</code> with the command:
</p>

<pre>
make install
</pre>

<p>
Alternatively, since the program consists of only the single self-contained
<code>jscoverage</code> executable, you may simply copy it to a suitable location
in your <code>PATH</code>.
</p>

<h2>Using JSCoverage</h2>

<p>
Using JSCoverage requires three steps:
</p>

<h3>1. Instrumenting code</h3>

<p>
The first step is to add instrumentation to your JavaScript code.  This is the function of the
<code>jscoverage</code> executable.  You must provide two arguments:
</p>

<pre>
jscoverage <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
</pre>

<p>
<var>SOURCE-DIRECTORY</var> is the directory containing the JavaScript code to be instrumented,
and <var>DESTINATION-DIRECTORY</var> is the name of the
directory to which <code>jscoverage</code> should output the instrumented code.
The <code>jscoverage</code> program will create <var>DESTINATION-DIRECTORY</var> if necessary and (recursively) copy
<var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>, instrumenting
any files ending with a <code>.js</code> extension.
</p>

<p>
For example, if you have a file
<code><var>SOURCE-DIRECTORY</var>/dir/index.html</code> referencing the script
<code><var>SOURCE-DIRECTORY</var>/dir/script.js</code>, then
<code>jscoverage</code> will create a copy of the HTML file at
<code><var>DESTINATION-DIRECTORY</var>/dir/index.html</code> and an instrumented
version of the script at
<code><var>DESTINATION-DIRECTORY</var>/dir/script.js</code>.
</p>

<table>
<tr>
<td><pre>
<var>SOURCE-DIRECTORY</var>/
  dir/
    index.html
    script.js

</pre></td>
<td class="arrow">&rarr;</td>
<td><pre>
<var>DESTINATION-DIRECTORY</var>/
  dir/
    index.html
    script.js [instrumented]
  jscoverage.html
</pre></td>
</tr>
</table>

<p>
In addition, <code>jscoverage</code> creates a file called <code>jscoverage.html</code>
which is used to execute the instrumented code.
</p>

<h3>2. Running instrumented code in the web application</h3>

<p>
Open <code>jscoverage.html</code> in your web browser.
The page contains a tabbed user interface:
</p>

<ul>
<li>The "Browser" tab is used to display pages with instrumented scripts.
<li>The "Summary" tab is used to display code coverage data.
<li>The "Source" tab is used to display JavaScript code, showing the number of times
each line of code was executed.
<li>The "About" tab displays information about the current version of JSCoverage.
</ul>

<img src="screenshot.png" alt="Screenshot">

<p>
The "Browser" tab contains an <code>&lt;iframe&gt;</code>, which is initially empty.
You can load a page into this frame by
entering its URL into the "URL" input field.  For example, to load
the file <code><var>DESTINATION-DIRECTORY</var>/dir/index.html</code>, you can
enter the relative URL <code>dir/index.html</code> into the input field.
</p>

<h3>3. Generating the coverage report</h3>

<p>
Once the JavaScript code in the page in the "Browser" tab has been executed, click on
the "Summary" tab.  This will display the current code coverage statistics.
</p>

<p>
As long as you do not reload the
<code>jscoverage.html</code> page, the coverage report statistics are
cumulative.  If you execute more JavaScript in the frame in the "Browser" tab (e.g., by clicking on a link to
another scripted page, or by reloading the frame containing a scripted
page) and switch to the "Summary" tab again,
the coverage report will combine the statistics from the previous report with any newly generated statistics.
Reloading <code>jscoverage.html</code> resets all code coverage statistics to zero.
</p>

<h2>Example</h2>

<p>
The JSCoverage distribution comes with a trivial example program in the <code>doc/example</code> directory.
You can view the file <code>doc/example/index.html</code> in your web browser to run the (uninstrumented) program.
To instrument this program, follow these steps:
</p>

<h3>1. Instrumenting code</h3>

<p>
From the main distribution directory, execute the command:
</p>

<pre>
jscoverage doc/example doc/instrumented
</pre>

<p>
This will create the directory <code>doc/instrumented</code> and
place an instrumented copy of the code from <code>doc/example</code> in <code>doc/instrumented</code>.
</p>

<h3>2. Executing instrumented code</h3>

<p>
You can load the file <code>doc/instrumented/jscoverage.html</code> in your web browser and type
the URL for the instrumented code in the "URL" input field.  Since a relative URL is accepted, you
can simply type <code>index.html</code> to load the page.
</p>

<p>
Alternatively, you can append the URL to the query string of the
<code>jscoverage.html</code> URL; for example, if you are in the main JSCoverage
directory and the Firefox executable is in your <code>PATH</code>, you can load
the <code>jscoverage.html</code> frameset and the <code>index.html</code> page
all in one command line:
</p>

<pre>
firefox "doc/instrumented/jscoverage.html?index.html"
</pre>

<img src="screenshot2.png" alt="Screenshot">

<p>
For this particular page, the JavaScript does not execute automatically:
you have to select one of the radio buttons to execute the code.
</p>

<img src="screenshot3.png" alt="Screenshot">

<h3>3. Generating the coverage report</h3>

<p>
Once you have executed the JavaScript code, you are instructed to click on the
"Summary" tab.
</p>

<img src="screenshot4.png" alt="Screenshot">

<p>
You can click the checkbox to show a list of statements missed during execution.
</p>

<img src="screenshot5.png" alt="Screenshot">

<p>
You can click one of the links to get a detailed view of a JavaScript source file.
</p>

<img src="screenshot6.png" alt="Screenshot">

<h2>Inverted mode</h2>

<p>
In some situations it may be difficult to execute your code within the
JSCoverage "Browser" tab. For example, the code may assume that it is running in
the top-level browser window, generating errors if it is executed from within a
frame. JSCoverage has an alternative mode of operation, called <dfn>inverted
mode</dfn>, which may be useful in this case.
</p>

<p>
Normally you load <code>jscoverage.html</code> in your web browser, and in its
"Browser" tab you launch your test code. In inverted mode, you do the
opposite: you load your test page directly in your web browser, and from there
you launch JSCoverage. To do this you need to add some code to your test page:
</p>

<pre>
window.open("path/to/jscoverage.html");
</pre>

<p>
The <code>"path/to/jscoverage.html"</code> should be a URL pointing to the
location of the <code>jscoverage.html</code> file (remember, this will be in the
top level of the <var>DESTINATION-DIRECTORY</var> you specified when running
the <code>jscoverage</code> executable).
</p>

<p>
You can place this code wherever you like in your page: for example, you could
attach it to a button:
</p>

<pre>
&lt;button onclick='window.open("path/to/jscoverage.html");'&gt;Coverage report&lt;/button&gt;
</pre>

<p>
Note that you <em>must</em> use a <code>window.open</code> call; simply making a
link to <code>jscoverage.html</code> is not sufficient.
</p>

<p>
An example is located in the <code>doc/example-inverted</code> directory.
You can instrument the code and launch the <code>index.html</code> page:
</p>

<pre>
jscoverage doc/example-inverted doc/instrumented-inverted
firefox "doc/instrumented-inverted/index.html"
</pre>

<p>
From this page, you select one of the radio buttons and then click the "Coverage
report" button to launch the JSCoverage report.
</p>

<h2>Command line options</h2>

<p>
The <code>jscoverage</code> program accepts the following options:
</p>

<dl>
<dt><code>-h</code>, <code>--help</code>
<dd>Display a brief help message.
<dt><code>-V</code>, <code>--version</code>
<dd>Display the version of the program.
<dt><code>-v</code>, <code>--verbose</code>
<dd>Explain what is being done.
<dt><code>--exclude=<var>PATH</var></code>
<dd>The command
<pre>
jscoverage --exclude=<var>PATH</var> <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
</pre>
copies <var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>
recursively, but does not copy <var>SOURCE-DIRECTORY</var>/<var>PATH</var>.
<var>PATH</var> must be a complete path relative to <var>SOURCE-DIRECTORY</var>.
<var>PATH</var> can be a file or a directory (in which case the directory and
its entire contents are skipped). This option may be given multiple times.
<dt><code>--no-instrument=<var>PATH</var></code>
<dd>The command
<pre>
jscoverage --no-instrument=<var>PATH</var> <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
</pre>
copies <var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>
recursively, but does not instrument any JavaScript code in
<var>SOURCE-DIRECTORY</var>/<var>PATH</var>. <var>PATH</var> must be a complete
path relative to <var>SOURCE-DIRECTORY</var>. <var>PATH</var> can be a
(JavaScript) file or a directory (in which case any JavaScript files located
anywhere underneath the directory are not instrumented). This option may be
given multiple times.
</dl>

<h2>Query string options</h2>

<p>
When accessing <code>jscoverage.html</code> in a web browser, you may provide a
query string consisting of options separated by ampersand (<code>&amp;</code>)
or semicolon (<code>;</code>). Any option not containing an equals sign
(<code>=</code>) is considered to be a URL which will be loaded in the "Browser"
tab.
</p>

<dl>
<dt><code>u=<var>URL</var></code>, <code>url=<var>URL</var></code>
<dd>Load <var>URL</var> in the "Browser" tab.  (This is the same as specifying
an option without an equals sign.)
<dt><code>m=<var>BOOLEAN</var></code>, <code>missing=<var>BOOLEAN</var></code>
<dd>Determines whether to initially display the "Missing" column in the "Summary"
tab.  <var>BOOLEAN</var> can be 
<code>true</code>, <code>t</code>, <code>yes</code>, <code>y</code>, <code>on</code>, <code>1</code>
(to display the "Missing" column), or
<code>false</code>, <code>f</code>, <code>no</code>, <code>n</code>, <code>off</code>, <code>0</code>
(to hide the "Missing" column).  By default, the "Missing" column is not displayed.
</dl>

<h2>Caveats</h2>

<ul>
<li>JSCoverage adds instrumentation to JavaScript code, which will slow down execution speed.
Expect instrumented code to take at least twice as much time to run.
<li>JSCoverage currently instruments only <code>.js</code> files; it does not instrument code in <code>&lt;script&gt;</code>
elements in HTML files.
<li>HTML files must use relative URLs to reference scripts.  If you use an absolute URL, your page will reference
the original uninstrumented script rather than the instrumented one, and no code coverage data will be collected.
<li>JSCoverage instruments physical lines of code rather than logical JavaScript statements; it works bests with code
that has exactly one statement per line.  If you put multiple statements on a line, or  split a line across two or more
statements, you may get strange results.
<li>JSCoverage uses frames.  Some web pages that use frames may not function properly when run under JSCoverage, especially
those which try to access the top-level frame (<code>window.top</code>, <code>target="_top"</code>, etc.).
<li>JSCoverage is alpha software.  Use at your own risk.
</ul>

<address>
  Copyright &copy; 2007 siliconforks.com<br>
  Last updated August 26, 2007<br>
  <a href="mailto:jscoverage@siliconforks.com">jscoverage@siliconforks.com</a>
</address>

</body>
</html>
1	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
2	<html>
3	<head>
4	<title>JSCoverage user manual</title>
5	<link type="text/css" href="doc.css" rel="stylesheet">
6	</head>
7	<body>
8
9	<h1>JSCoverage user manual</h1>
10
11	<p>
12	JSCoverage is a tool used to measure code coverage in JavaScript
13	programs.
14	</p>
15
16	<p>
17	JSCoverage has two components:
18	</p>
19
20	<ol>
21	<li>An executable program which is used to add instrumentation to JavaScript code.
22	<li>A web application which is used to execute instrumented code and generate a
23	code coverage report.
24	</ol>
25
26	<h2>Installing JSCoverage</h2>
27
28	<p>
29	You can compile JSCoverage on GNU/Linux or Microsoft Windows, using GCC. On
30	Windows you will require <a href="http://cygwin.com/">Cygwin</a> or <a
31	href="http://mingw.org/">MinGW/MSYS</a>.
32	</p>
33
34	<p>
35	You can extract and compile the code with the following commands:
36	</p>
37
38	<pre>
39	tar jxvf jscoverage-0.3.tar.bz2
40	cd jscoverage-0.3/
41	./configure
42	make
43	</pre>
44
45	<p>
46	This will create the <code>jscoverage</code> executable (<code>jscoverage.exe</code> on Windows).
47	You can install the executable in <code>/usr/local</code> with the command:
48	</p>
49
50	<pre>
51	make install
52	</pre>
53
54	<p>
55	Alternatively, since the program consists of only the single self-contained
56	<code>jscoverage</code> executable, you may simply copy it to a suitable location
57	in your <code>PATH</code>.
58	</p>
59
60	<h2>Using JSCoverage</h2>
61
62	<p>
63	Using JSCoverage requires three steps:
64	</p>
65
66	<h3>1. Instrumenting code</h3>
67
68	<p>
69	The first step is to add instrumentation to your JavaScript code. This is the function of the
70	<code>jscoverage</code> executable. You must provide two arguments:
71	</p>
72
73	<pre>
74	jscoverage <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
75	</pre>
76
77	<p>
78	<var>SOURCE-DIRECTORY</var> is the directory containing the JavaScript code to be instrumented,
79	and <var>DESTINATION-DIRECTORY</var> is the name of the
80	directory to which <code>jscoverage</code> should output the instrumented code.
81	The <code>jscoverage</code> program will create <var>DESTINATION-DIRECTORY</var> if necessary and (recursively) copy
82	<var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>, instrumenting
83	any files ending with a <code>.js</code> extension.
84	</p>
85
86	<p>
87	For example, if you have a file
88	<code><var>SOURCE-DIRECTORY</var>/dir/index.html</code> referencing the script
89	<code><var>SOURCE-DIRECTORY</var>/dir/script.js</code>, then
90	<code>jscoverage</code> will create a copy of the HTML file at
91	<code><var>DESTINATION-DIRECTORY</var>/dir/index.html</code> and an instrumented
92	version of the script at
93	<code><var>DESTINATION-DIRECTORY</var>/dir/script.js</code>.
94	</p>
95
96	<table>
97	<tr>
98	<td><pre>
99	<var>SOURCE-DIRECTORY</var>/
100	dir/
101	index.html
102	script.js
103
104	</pre></td>
105	<td class="arrow">→</td>
106	<td><pre>
107	<var>DESTINATION-DIRECTORY</var>/
108	dir/
109	index.html
110	script.js [instrumented]
111	jscoverage.html
112	</pre></td>
113	</tr>
114	</table>
115
116	<p>
117	In addition, <code>jscoverage</code> creates a file called <code>jscoverage.html</code>
118	which is used to execute the instrumented code.
119	</p>
120
121	<h3>2. Running instrumented code in the web application</h3>
122
123	<p>
124	Open <code>jscoverage.html</code> in your web browser.
125	The page contains a tabbed user interface:
126	</p>
127
128	<ul>
129	<li>The "Browser" tab is used to display pages with instrumented scripts.
130	<li>The "Summary" tab is used to display code coverage data.
131	<li>The "Source" tab is used to display JavaScript code, showing the number of times
132	each line of code was executed.
133	<li>The "About" tab displays information about the current version of JSCoverage.
134	</ul>
135
136	<img src="screenshot.png" alt="Screenshot">
137
138	<p>
139	The "Browser" tab contains an <code><iframe></code>, which is initially empty.
140	You can load a page into this frame by
141	entering its URL into the "URL" input field. For example, to load
142	the file <code><var>DESTINATION-DIRECTORY</var>/dir/index.html</code>, you can
143	enter the relative URL <code>dir/index.html</code> into the input field.
144	</p>
145
146	<h3>3. Generating the coverage report</h3>
147
148	<p>
149	Once the JavaScript code in the page in the "Browser" tab has been executed, click on
150	the "Summary" tab. This will display the current code coverage statistics.
151	</p>
152
153	<p>
154	As long as you do not reload the
155	<code>jscoverage.html</code> page, the coverage report statistics are
156	cumulative. If you execute more JavaScript in the frame in the "Browser" tab (e.g., by clicking on a link to
157	another scripted page, or by reloading the frame containing a scripted
158	page) and switch to the "Summary" tab again,
159	the coverage report will combine the statistics from the previous report with any newly generated statistics.
160	Reloading <code>jscoverage.html</code> resets all code coverage statistics to zero.
161	</p>
162
163	<h2>Example</h2>
164
165	<p>
166	The JSCoverage distribution comes with a trivial example program in the <code>doc/example</code> directory.
167	You can view the file <code>doc/example/index.html</code> in your web browser to run the (uninstrumented) program.
168	To instrument this program, follow these steps:
169	</p>
170
171	<h3>1. Instrumenting code</h3>
172
173	<p>
174	From the main distribution directory, execute the command:
175	</p>
176
177	<pre>
178	jscoverage doc/example doc/instrumented
179	</pre>
180
181	<p>
182	This will create the directory <code>doc/instrumented</code> and
183	place an instrumented copy of the code from <code>doc/example</code> in <code>doc/instrumented</code>.
184	</p>
185
186	<h3>2. Executing instrumented code</h3>
187
188	<p>
189	You can load the file <code>doc/instrumented/jscoverage.html</code> in your web browser and type
190	the URL for the instrumented code in the "URL" input field. Since a relative URL is accepted, you
191	can simply type <code>index.html</code> to load the page.
192	</p>
193
194	<p>
195	Alternatively, you can append the URL to the query string of the
196	<code>jscoverage.html</code> URL; for example, if you are in the main JSCoverage
197	directory and the Firefox executable is in your <code>PATH</code>, you can load
198	the <code>jscoverage.html</code> frameset and the <code>index.html</code> page
199	all in one command line:
200	</p>
201
202	<pre>
203	firefox "doc/instrumented/jscoverage.html?index.html"
204	</pre>
205
206	<img src="screenshot2.png" alt="Screenshot">
207
208	<p>
209	For this particular page, the JavaScript does not execute automatically:
210	you have to select one of the radio buttons to execute the code.
211	</p>
212
213	<img src="screenshot3.png" alt="Screenshot">
214
215	<h3>3. Generating the coverage report</h3>
216
217	<p>
218	Once you have executed the JavaScript code, you are instructed to click on the
219	"Summary" tab.
220	</p>
221
222	<img src="screenshot4.png" alt="Screenshot">
223
224	<p>
225	You can click the checkbox to show a list of statements missed during execution.
226	</p>
227
228	<img src="screenshot5.png" alt="Screenshot">
229
230	<p>
231	You can click one of the links to get a detailed view of a JavaScript source file.
232	</p>
233
234	<img src="screenshot6.png" alt="Screenshot">
235
236	<h2>Inverted mode</h2>
237
238	<p>
239	In some situations it may be difficult to execute your code within the
240	JSCoverage "Browser" tab. For example, the code may assume that it is running in
241	the top-level browser window, generating errors if it is executed from within a
242	frame. JSCoverage has an alternative mode of operation, called <dfn>inverted
243	mode</dfn>, which may be useful in this case.
244	</p>
245
246	<p>
247	Normally you load <code>jscoverage.html</code> in your web browser, and in its
248	"Browser" tab you launch your test code. In inverted mode, you do the
249	opposite: you load your test page directly in your web browser, and from there
250	you launch JSCoverage. To do this you need to add some code to your test page:
251	</p>
252
253	<pre>
254	window.open("path/to/jscoverage.html");
255	</pre>
256
257	<p>
258	The <code>"path/to/jscoverage.html"</code> should be a URL pointing to the
259	location of the <code>jscoverage.html</code> file (remember, this will be in the
260	top level of the <var>DESTINATION-DIRECTORY</var> you specified when running
261	the <code>jscoverage</code> executable).
262	</p>
263
264	<p>
265	You can place this code wherever you like in your page: for example, you could
266	attach it to a button:
267	</p>
268
269	<pre>
270	<button onclick='window.open("path/to/jscoverage.html");'>Coverage report</button>
271	</pre>
272
273	<p>
274	Note that you <em>must</em> use a <code>window.open</code> call; simply making a
275	link to <code>jscoverage.html</code> is not sufficient.
276	</p>
277
278	<p>
279	An example is located in the <code>doc/example-inverted</code> directory.
280	You can instrument the code and launch the <code>index.html</code> page:
281	</p>
282
283	<pre>
284	jscoverage doc/example-inverted doc/instrumented-inverted
285	firefox "doc/instrumented-inverted/index.html"
286	</pre>
287
288	<p>
289	From this page, you select one of the radio buttons and then click the "Coverage
290	report" button to launch the JSCoverage report.
291	</p>
292
293	<h2>Command line options</h2>
294
295	<p>
296	The <code>jscoverage</code> program accepts the following options:
297	</p>
298
299	<dl>
300	<dt><code>-h</code>, <code>--help</code>
301	<dd>Display a brief help message.
302	<dt><code>-V</code>, <code>--version</code>
303	<dd>Display the version of the program.
304	<dt><code>-v</code>, <code>--verbose</code>
305	<dd>Explain what is being done.
306	<dt><code>--exclude=<var>PATH</var></code>
307	<dd>The command
308	<pre>
309	jscoverage --exclude=<var>PATH</var> <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
310	</pre>
311	copies <var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>
312	recursively, but does not copy <var>SOURCE-DIRECTORY</var>/<var>PATH</var>.
313	<var>PATH</var> must be a complete path relative to <var>SOURCE-DIRECTORY</var>.
314	<var>PATH</var> can be a file or a directory (in which case the directory and
315	its entire contents are skipped). This option may be given multiple times.
316	<dt><code>--no-instrument=<var>PATH</var></code>
317	<dd>The command
318	<pre>
319	jscoverage --no-instrument=<var>PATH</var> <var>SOURCE-DIRECTORY</var> <var>DESTINATION-DIRECTORY</var>
320	</pre>
321	copies <var>SOURCE-DIRECTORY</var> to <var>DESTINATION-DIRECTORY</var>
322	recursively, but does not instrument any JavaScript code in
323	<var>SOURCE-DIRECTORY</var>/<var>PATH</var>. <var>PATH</var> must be a complete
324	path relative to <var>SOURCE-DIRECTORY</var>. <var>PATH</var> can be a
325	(JavaScript) file or a directory (in which case any JavaScript files located
326	anywhere underneath the directory are not instrumented). This option may be
327	given multiple times.
328	</dl>
329
330	<h2>Query string options</h2>
331
332	<p>
333	When accessing <code>jscoverage.html</code> in a web browser, you may provide a
334	query string consisting of options separated by ampersand (<code>&</code>)
335	or semicolon (<code>;</code>). Any option not containing an equals sign
336	(<code>=</code>) is considered to be a URL which will be loaded in the "Browser"
337	tab.
338	</p>
339
340	<dl>
341	<dt><code>u=<var>URL</var></code>, <code>url=<var>URL</var></code>
342	<dd>Load <var>URL</var> in the "Browser" tab. (This is the same as specifying
343	an option without an equals sign.)
344	<dt><code>m=<var>BOOLEAN</var></code>, <code>missing=<var>BOOLEAN</var></code>
345	<dd>Determines whether to initially display the "Missing" column in the "Summary"
346	tab. <var>BOOLEAN</var> can be
347	<code>true</code>, <code>t</code>, <code>yes</code>, <code>y</code>, <code>on</code>, <code>1</code>
348	(to display the "Missing" column), or
349	<code>false</code>, <code>f</code>, <code>no</code>, <code>n</code>, <code>off</code>, <code>0</code>
350	(to hide the "Missing" column). By default, the "Missing" column is not displayed.
351	</dl>
352
353	<h2>Caveats</h2>
354
355	<ul>
356	<li>JSCoverage adds instrumentation to JavaScript code, which will slow down execution speed.
357	Expect instrumented code to take at least twice as much time to run.
358	<li>JSCoverage currently instruments only <code>.js</code> files; it does not instrument code in <code><script></code>
359	elements in HTML files.
360	<li>HTML files must use relative URLs to reference scripts. If you use an absolute URL, your page will reference
361	the original uninstrumented script rather than the instrumented one, and no code coverage data will be collected.
362	<li>JSCoverage instruments physical lines of code rather than logical JavaScript statements; it works bests with code
363	that has exactly one statement per line. If you put multiple statements on a line, or split a line across two or more
364	statements, you may get strange results.
365	<li>JSCoverage uses frames. Some web pages that use frames may not function properly when run under JSCoverage, especially
366	those which try to access the top-level frame (<code>window.top</code>, <code>target="_top"</code>, etc.).
367	<li>JSCoverage is alpha software. Use at your own risk.
368	</ul>
369
370	<address>
371	Copyright © 2007 siliconforks.com<br>
372	Last updated August 26, 2007<br>
373	<a href="mailto:jscoverage@siliconforks.com">jscoverage@siliconforks.com</a>
374	</address>
375
376	</body>
377	</html>