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mirror of https://github.com/adobe/brackets.git synced 2024-11-20 09:53:00 +01:00

Switch JSLint to a submodule

This commit is contained in:
Tomás Malbrán 2013-07-15 23:43:15 -03:00
parent 73447e480a
commit 8f8f7c3b5c
8 changed files with 4 additions and 8273 deletions

3
.gitmodules vendored
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[submodule "src/thirdparty/i18n"]
path = src/thirdparty/i18n
url = https://github.com/requirejs/i18n.git
[submodule "src/extensions/default/JSLint/thirdparty/jslint"]
path = src/extensions/default/JSLint/thirdparty/jslint
url = git://github.com/douglascrockford/JSLint.git

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Subproject commit eec32d4b4bc7945672c49a5ffdf4dc6c87b7058b

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JSLint, The JavaScript Code Quality Tool
Douglas Crockford
douglas@crockford.com
2011-12-21
jslint.js contains the fully commented JSLINT function.
jslint.html runs the JSLINT function in a web page. The page also depends
on adsafe.js [www.ADsafe.org] and json2.js [www.JSON.org] (which are not
included in this project) and intercept.js and init_ui.js (which are). The
js files should all be minified, and all except init_ui.js are concatenated
together to form web_jslint.js.
intercept.js augments ADsafe, giving widgets access to the clock, cookies,
and the JSLINT function.
init_ui.js hooks the HTML ui components to ADsafe.
lint.html describes JSLint's usage. Please read it.
Direct questions and comments to http://tech.groups.yahoo.com/group/jslint_com/.
JSLint can be run anywhere that JavaScript (or Java) can run. See for example
http://tech.groups.yahoo.com/group/jslint_com/database?method=reportRows&tbl=1
The place to express yourself in programming is in the quality of your ideas,
and the efficiency of execution. The role of style is the same as in
literature. A great writer doesn't express himself by putting the spaces
before his commas instead of after, or by putting extra spaces inside his
parentheses. A great writer will slavishly conform to some rules of style,
and that in no way constrains his power to express himself creatively.
See for example William Strunk's The Elements of Style
[http://www.crockford.com/wrrrld/style.html].
This applies to programming as well. Conforming to a consistent style
improves readability, and frees you to express yourself in ways that matter.
JSLint here plays the part of a stern but benevolent editor, helping you to
get the style right so that you can focus your creative energy where it is
most needed.

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// init_ui.js
// 2011-12-08
// This is the web browser companion to fulljslint.js. It is an ADsafe
// lib file that implements a web ui by adding behavior to the widget's
// html tags.
// It stores a function in lib.init_ui. Calling that function will
// start up the JSLint widget ui.
// option = {adsafe: true, fragment: false}
/*properties check, cookie, each, edition, get, getCheck, getTitle, getValue,
has, indent, isArray, join, jslint, length, lib, maxerr, maxlen, on,
predef, push, q, select, set, split, stringify, style, target, tree, value
*/
ADSAFE.lib("init_ui", function (lib) {
'use strict';
return function (dom) {
var table = dom.q('#JSLINT_TABLE'),
boxes = table.q('span'),
indent = dom.q('#JSLINT_INDENT'),
input = dom.q('#JSLINT_INPUT'),
jslintstring = dom.q('#JSLINT_JSLINTSTRING'),
maxerr = dom.q('#JSLINT_MAXERR'),
maxlen = dom.q('#JSLINT_MAXLEN'),
option = lib.cookie.get(),
output = dom.q('#JSLINT_OUTPUT'),
tree = dom.q('#JSLINT_TREE'),
predefined = dom.q('#JSLINT_PREDEF');
function show_jslint_control() {
// Build and display a /*jslint*/ control comment.
// The comment can be copied into a .js file.
var a = [];
boxes.each(function (bunch) {
var name = bunch.getTitle(),
value = ADSAFE.get(option, name);
if (typeof value === 'boolean') {
if (name !== 'adsafe' && name !== 'safe') {
a.push(name + ': ' + value);
}
bunch.style('backgroundColor', value ? 'black' : 'white');
} else {
bunch.style('backgroundColor', 'gainsboro');
}
});
if (typeof option.maxerr === 'number' && option.maxerr >= 0) {
a.push('maxerr: ' + String(option.maxerr));
}
if (typeof option.maxlen === 'number' && option.maxlen >= 0) {
a.push('maxlen: ' + String(option.maxlen));
}
if (typeof option.indent === 'number' && option.indent >= 0) {
a.push('indent: ' + String(option.indent));
}
jslintstring.value('/*jslint ' + a.join(', ') + ' */');
// Make a JSON cookie of the option object.
lib.cookie.set(option);
}
function show_options() {
indent.value(String(option.indent));
maxlen.value(String(option.maxlen || ''));
maxerr.value(String(option.maxerr));
predefined.value(ADSAFE.isArray(option.predef)
? option.predef.join(',')
: '');
show_jslint_control();
}
function update_box(event) {
// Boxes are tristate, cycling true, false, undefined.
var title = event.target.getTitle();
if (title) {
ADSAFE.set(option, title,
ADSAFE.get(option, title) === true
? false
: ADSAFE.get(option, title) === false
? undefined
: true);
}
show_jslint_control();
}
function update_number(event) {
var value = event.target.getValue();
if (value.length === 0 || +value < 0 || !isFinite(value)) {
value = '';
ADSAFE.set(option, event.target.getTitle(), undefined);
} else {
ADSAFE.set(option, event.target.getTitle(), +value);
}
event.target.value(String(value));
show_jslint_control();
}
function update_list(event) {
var value = event.target.getValue().split(/\s*,\s*/);
ADSAFE.set(option, event.target.getTitle(), value);
event.target.value(value.join(', '));
show_jslint_control();
}
// Restore the options from a JSON cookie.
if (!option || typeof option !== 'object') {
option = {
indent: 4,
maxerr: 50
};
} else {
option.indent = typeof option.indent === 'number' && option.indent >= 0
? option.indent
: 4;
option.maxerr = typeof option.maxerr === 'number' && option.maxerr >= 0
? option.maxerr
: 50;
}
show_options();
// Display the edition.
dom.q('#JSLINT_EDITION').value('Edition ' + lib.edition());
// Add click event handlers to the [JSLint] and [clear] buttons.
dom.q('input&jslint').on('click', function () {
tree.value('');
// Call JSLint and display the report.
tree.value(String(lib.jslint(input.getValue(), option, output) / 1000) + ' seconds.');
input.select();
return false;
});
dom.q('input&tree').on('click', function () {
output.value('Tree:');
tree.value(JSON.stringify(lib.tree(), [
'label', 'id', 'string', 'number', 'arity', 'name', 'first',
'second', 'third', 'block', 'else', 'quote', 'flag', 'type'
], 4));
input.select();
});
dom.q('input&clear').on('click', function () {
output.value('');
tree.value('');
input.value('').select();
});
dom.q('#JSLINT_CLEARALL').on('click', function () {
option = {
indent: 4,
maxerr: 50
};
show_options();
});
table.on('click', update_box);
indent.on('change', update_number);
maxerr.on('change', update_number);
maxlen.on('change', update_number);
predefined.on('change', update_list);
input
.on('change', function () {
output.value('');
})
.select();
};
});

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// intercept.js
// 2011-06-13
// This file makes it possible for JSLint to run as an ADsafe widget by
// adding lib features.
// It provides a JSON cookie facility. Each widget is allowed to create a
// single JSON cookie.
// It also provides a way for the widget to call JSLint. The widget cannot
// call JSLint directly because it is loaded as a global variable. I don't
// want to change that because other versions of JSLint depend on that.
// And it provides access to the syntax tree that JSLint constructed.
/*jslint nomen: true, unparam: true */
/*global ADSAFE, document, JSLINT */
/*properties ___nodes___, _intercept, cookie, edition, get, getTime,
indexOf, innerHTML, jslint, length, now, parse, replace, report, set,
setTime, slice, stringify, toGMTString, tree
*/
ADSAFE._intercept(function (id, dom, lib, bunch) {
"use strict";
// Give every widget access to a JSON cookie. The name of the cookie will be
// the same as the id of the widget.
lib.cookie = {
get: function () {
// Get the raw cookie. Extract this widget's cookie, and parse it.
var c = ' ' + document.cookie + ';',
s = c.indexOf((' ' + id + '=')),
v;
try {
if (s >= 0) {
s += id.length + 2;
v = JSON.parse(c.slice(s, c.indexOf(';', s)));
}
} catch (ignore) {}
return v;
},
set: function (value) {
// Set a cookie. It must be under 2000 in length. Escapify equal sign
// and semicolon if necessary.
var d,
j = JSON.stringify(value)
.replace(/[=]/g, '\\u003d')
.replace(/[;]/g, '\\u003b');
if (j.length < 2000) {
d = new Date();
d.setTime(d.getTime() + 1e9);
document.cookie = id + "=" + j + ';expires=' + d.toGMTString();
}
}
};
});
ADSAFE._intercept(function (id, dom, lib, bunch) {
"use strict";
// Give only the JSLINT_ widget access to the JSLINT function.
// We add a jslint function to its lib that calls JSLINT and
// then calls JSLINT.report, and stuffs the html result into
// a node provided by the widget. A widget does not get direct
// access to nodes.
// We also add an edition function to the lib that gives the
// widget access to the current edition string.
var now = Date.now || function () {
return new Date().getTime();
};
if (id === 'JSLINT_') {
lib.jslint = function (source, options, output) {
output.___nodes___[0].innerHTML = "Working.";
var after, report, before = now();
JSLINT(source, options);
report = JSLINT.report();
after = now();
output.___nodes___[0].innerHTML = report;
return after - before;
};
lib.edition = function () {
return JSLINT.edition;
};
lib.tree = function () {
return JSLINT.tree;
};
}
});

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<html>
<head><title>JSLint, The JavaScript Code Quality Tool</title>
<link rel="icon" type="image/gif" href="http://www.JSLint.com/favicon.gif">
<style>
#JSLINT_TABLE td span {
border: 2px solid black;
}
table {
cursor: pointer;
}
i {
font-family: serif;
font-style: italic;
}
p {
padding-left: 10pt;
}
input[type="button"] {
background-color: navajowhite;
border: 2px solid black;
color: black;
}
input[type="button"]:hover {
background-color: lightsteelblue;
text-decoration: underline;
}
input[type="button"]:active {
background-color: indianred;
text-decoration: none;
}
input[type="text"] {
border: 2px solid black;
text-align: center;
}
a:link {
color: darkblue;
}
a:visited {
color: purple;
}
a:hover {
color: blue;
}
a:active {
color: red;
}
body {
background-color: gainsboro;
padding-left: 5%;
padding-right: 5%;
text-align: center;
}
.leftcolumn {
float: left;
margin: 1em;
}
#errors {
margin: 1em;
border: 2px solid black;
padding: 1em;
background-color: mistyrose;
}
#errors p {
margin-left: 2em;
}
#errors p.evidence {
margin-left: 0;
font-family: monospace;
}
#functions {
background-color: white;
}
#members {
background-color: peachpuff;
}
#functions, #members {
border: 2px solid black;
font-family: monospace;
margin: 1em;
padding: 1em;
}
#functions div {
margin-left: 10em;
text-indent: -5em;
}
#functions div.function {
margin-left: 0;
text-indent: 0;
}
#JSLINT_OUTPUT {
text-align: left;
}
#JSLINT_INPUT{
border: 2px solid black;
color: black;
font-family: monospace;
height: 3in;
overflow: auto;
padding: 0.5em;
width: 100%;
}
#JSLINT_JSLINTSTRING {
background-color: peachpuff;
border: 2px solid black;
font-family: monospace;
margin: 1em;
padding: 1em;
}
#JSLINT_OPTIONS {
border: 2px solid black;
color: black;
margin: 1em;
padding: 8px;
text-align: left;
background-color: linen;
}
#JSLINT_TREE, #JSLINT_FIELDS {
text-align: left;
}
</style></head>
<body>
<table border="0" cols="2"><tbody>
<tr>
<td><img src="jslint.gif" width="383" height="120" alt="JSLint"> </td>
<td valign="middle" align="left">
<p><big>The&nbsp;<a href="http://javascript.crockford.com/">JavaScript</a>&nbsp;Code Quality Tool</big></p>
<p id=JSLINT_EDITION></p>
<p>
<a href="http://www.JSLint.com/lint.html">Read the instructions.</a>&nbsp;
<a href="#JSLINT_OPTIONS">Set the options.</a>&nbsp;
<a href="http://www.amazon.com/exec/obidos/ASIN/0596517742/wrrrldwideweb"
target="_blank">Enjoy&nbsp;<i>The Good Parts</i>.</a></p>
</td></tr></tbody></table>
<script src="web_jslint.js">
// json2.js+jslint.js+adsafe.js+intercept.js
</script>
<div id="JSLINT_">
<p style="background-color: transparent;"><textarea id="JSLINT_INPUT"></textarea></p>
<p>
<input type="button" name="jslint" value="JSLint">
&nbsp; &nbsp;
<input type="button" name="tree" value="Syntax Tree">
&nbsp; &nbsp;
<input type="button" name="clear" value="clear">
</p>
<div id="JSLINT_OUTPUT">
<div style="text-align: center;">Paste your program into the text box
above and click a&nbsp;<input type="button" name="jslint" value="JSLint">&nbsp;
button.</div>
<div style="text-align: center; margin: 1em; border: 2px solid black; padding: 1em; background-color: papayawhip;">
<big>Warning! JSLint will hurt your feelings.</big></div>
</div>
<pre id="JSLINT_TREE"></pre>
<p>
<input type="button" name="jslint" value="JSLint">
&nbsp; &nbsp;
<input type="button" name="tree" value="Syntax Tree">
&nbsp; &nbsp;
<input type="button" name="clear" value="clear">
&nbsp; &nbsp;
<input type="button" id="JSLINT_CLEARALL" value="Clear All Options">
</p>
<p id="JSLINT_OPTIONS">
<table id="JSLINT_TABLE" border="0">
<tr>
<td><span title="devel">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="devel">Assume&nbsp;<code>console</code>,&nbsp;<code>alert</code>,&nbsp;...</td>
<td><span title="bitwise">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="bitwise">Tolerate bitwise operators</td>
<td><span title="regexp">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="regexp">Tolerate&nbsp;<tt>.</tt>&nbsp;and&nbsp;<tt>[^</tt>...<tt>]</tt>&nbsp;in&nbsp;/RegExp/</td>
</tr>
<tr>
<td><span title="browser">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="browser">Assume a browser</td>
<td><span title="confusion">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="confusion">Tolerate&nbsp;type&nbsp;confusion</td>
<td><span title="undef">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="undef">Tolerate&nbsp;misordered&nbsp;definitions</td>
</tr>
<tr>
<td><span title="node">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="node">Assume&nbsp;<a href="http://nodejs.org/">Node.js</a></td>
<td><span title="continue">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="continue">Tolerate&nbsp;<tt>continue</tt></td>
<td><span title="unparam">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="unparam">Tolerate&nbsp;unused&nbsp;parameters</td>
</tr>
<tr>
<td><span title="rhino">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="rhino">Assume&nbsp;<a href="http://www.mozilla.org/rhino/">Rhino</a></td>
<td><span title="debug">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="debug">Tolerate&nbsp;<tt>debugger</tt>&nbsp;statements</td>
<td><span title="sloppy">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="sloppy">Tolerate&nbsp;missing&nbsp;<code>'use&nbsp;strict'</code>&nbsp;pragma</td>
</tr>
<tr>
<td><span title="widget">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="widget">Assume a&nbsp;<a href="http://widgets.yahoo.com/tools/">Yahoo Widget</a></td>
<td><span title="eqeq">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="eqeq">Tolerate&nbsp;<code>==</code>&nbsp;and&nbsp;<code>!=</code></td>
<td><span title="sub">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="sub">Tolerate&nbsp;inefficient&nbsp;subscripting</td>
</tr>
<tr>
<td><span title="windows">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="windows">Assume&nbsp;Windows</td>
<td><span title="es5">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="es5">Tolerate&nbsp;ES5&nbsp;syntax</td>
<td><span title="vars">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="vars">Tolerate many&nbsp;<tt>var</tt>&nbsp;statements per function</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td><span title="evil">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="evil">Tolerate&nbsp;<tt>eval</tt></td>
<td><span title="white">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="white">Tolerate&nbsp;messy&nbsp;white space</td>
</tr>
<tr>
<td><span title="passfail">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="passfail">Stop&nbsp;on&nbsp;first&nbsp;error</td>
<td><span title="forin">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="forin">Tolerate&nbsp;<a href="http://yuiblog.com/blog/2006/09/26/for-in-intrigue/">unfiltered</a>&nbsp;<tt>for</tt>&nbsp;<tt>in</tt></td>
<td><span title="css">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="css">Tolerate&nbsp;CSS&nbsp;workarounds</td>
</tr>
<tr>
<td>&nbsp;</td>
<td>&nbsp;</td>
<td><span title="newcap">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="newcap">Tolerate uncapitalized constructors</td>
<td><span title="cap">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="cap">Tolerate&nbsp;<tt>HTML</tt>&nbsp;case</td>
</tr>
<tr>
<td><span title="safe">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="safe">Safe&nbsp;Subset</td>
<td><span title="nomen">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="nomen">Tolerate dangling&nbsp;<tt>_</tt>&nbsp;in identifiers</td>
<td><span title="on">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="on">Tolerate&nbsp;<tt>HTML</tt>&nbsp;event handlers</td>
</tr>
<tr>
<td><span title="adsafe">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="adsafe">Verify&nbsp;<a href="http://www.ADsafe.org">ADsafe</a></td>
<td><span title="plusplus">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="plusplus">Tolerate&nbsp;<tt>++</tt>&nbsp;and&nbsp;<tt>--</tt></td>
<td><span title="fragment">&nbsp;&nbsp;&nbsp;&nbsp;</span></td>
<td title="fragment">Tolerate&nbsp;<tt>HTML</tt>&nbsp;fragments</td>
</tr>
</table>
<p><br clear=all>
</p>
<div id=JSLINT_FIELDS>
<input id="JSLINT_INDENT" type="text" size="2" title="indent" value="" autocomplete=off> <label for="JSLINT_INDENT" title="indent">Indentation</label><br>
<input id="JSLINT_MAXLEN" type="text" size="2" title="maxlen" value="" autocomplete=off> <label for="JSLINT_MAXLEN" title="maxlen">Maximum line length</label><br>
<input id="JSLINT_MAXERR" type="text" size="2" title="maxerr" value="" autocomplete=off> <label for="JSLINT_MAXERR" title="maxerr">Maximum number of errors</label><br>
<label title=predef for="JSLINT_PREDEF">Predefined&nbsp;<small>(&nbsp;<code>,</code>&nbsp;separated)</small></label>&nbsp;<input id="JSLINT_PREDEF" type="text" size="72" autocomplete=off title=predef>
</div>
</p>
<p id="JSLINT_JSLINTSTRING"></p>
<p> Copyright 2002&nbsp;<a href="http://www.JSLint.com/lint.html">Douglas
Crockford.</a>&nbsp;<a target="_blank" href="http://www.crockford.com/">All
Rights Reserved Wrrrldwide and Beyond!</a> <br>
<a href="http://javascript.crockford.com/code.html" target="_blank">Code
Conventions for the JavaScript Programming Language.</a><br>
<a href="http://tech.groups.yahoo.com/group/jslint_com/" target="_blank">Join
the JSLint Group.</a> </p>
<script>
ADSAFE.id("JSLINT_");
</script>
<script src="init_ui.js"></script>
<script>
ADSAFE.go("JSLINT_", function (dom, lib) {
"use strict";
lib.init_ui(dom);
});
</script>
</div>
<a href="http://www.JSLint.com/"><img src="jslintpill.gif" width="36" height="17" border="0"></a>
<a href="http://tech.groups.yahoo.com/group/jslint_com/"><img src="y.gif" width="31" height="17" border="0"></a>
<a href="https://github.com/douglascrockford/JSLint"><img src="github.gif" width="39" height="16" border="0"></a>
<a href="http://www.ADsafe.org/"><img src="adsafepill.gif" width="36" height="17" border="0"></a>
<a href="http://www.JSON.org/"><img src="jsonpill.gif" width="36" height="17" border="0"></a>
<a href="http://www.1and1.com/?k_id=10219574"><img src="1and1pill.gif" width="36" height="17" border="0"></a>
</body></html>

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<html>
<head>
<title>JSLint: The JavaScript Code Quality Tool</title>
<link rel="icon" type="image/gif" href="http://www.JSLint.com/favicon.gif">
<style>
body {
background-color: linen;
margin-left: 8%;
margin-right: 8%;
}
pre {
margin-left: 40px;
}
table {
margin: 10px;
border: 0px;
}
th, td {
border: black solid 1pt;
padding-left: 10px;
padding-right: 10px;
vertical-align: top;
}
th {
background-color: thistle;
}
td {
background-color: white;
}
#top table {
margin: 0px;
}
#top td {
background-color: linen;
border: 0pt;
vertical-align: middle;
}
ul {
list-style-type: square;
}
input[type="button"] {
border: 2px solid black;
}
a:link {
color: darkblue;
}
a:visited {
color: purple;
}
a:hover {
color: blue;
text-decoration: underline;
}
a:active {color: red;
}
</style>
</head>
<body bgcolor="gainsboro">
<table id="top" border="0">
<tr>
<td><img src="jslint.gif" width="383" height="120" alt="JSLint"> </td>
<td>
<p><big><code>JSLint</code>: The
<a href="http://javascript.crockford.com/">JavaScript</a> Code Quality Tool</big></p>
<p><a href="http://www.crockford.com/" target="_top">&copy;2002 Douglas Crockford</a></p>
</td>
</tr>
</table>
<br clear="all">
<h2 id=warning>Warning!</h2>
<p><a href="http://www.JSLint.com" target="_blank"><code>JSLint</code></a>
will hurt your feelings.</p>
<h2 id=what>What is <code>JSLint</code>?</h2>
<p><a href="http://www.JSLint.com" target="_blank"><code>JSLint</code></a>
is a JavaScript program that looks for problems in JavaScript programs.
It is a code quality tool.</p>
<p>When <a href="http://en.wikipedia.org/wiki/C_programming_language">C</a>
was a <a href="http://cm.bell-labs.com/cm/cs/who/dmr/chist.html">young</a>
programming language, there were several common programming errors that
were not caught by the primitive compilers, so an accessory program called
<code><a href="http://en.wikipedia.org/wiki/Lint_programming_tool">lint</a></code>
was developed that would scan a source file, looking for problems.</p>
<p>As the language matured, the definition of the language was
strengthened to eliminate some insecurities, and compilers got better
at issuing warnings. <code>lint</code> is no longer needed.</p>
<p><a href="http://javascript.crockford.com/">JavaScript</a> is a young-for-its-age
language. It was originally intended to do small tasks in webpages, tasks
for which Java was too heavy and clumsy. But JavaScript is a very capable
language, and it is now being used in larger projects. Many of the features
that were intended to make the language easy to use are troublesome when projects become complicated. A <code>lint</code> for JavaScript is needed: <a href="http://www.JSLint.com/"><code>JSLint</code></a>,
a JavaScript syntax checker and validator.</p>
<p><code>JSLint</code> takes a JavaScript source and scans it. If it finds
a problem, it returns a message describing the problem and an approximate
location within the source. The problem is not necessarily a syntax error,
although it often is. <code>JSLint</code> looks at some style conventions
as well as structural problems. It does not prove that your program is
correct. It just provides another set of eyes to help spot problems.</p>
<p><code>JSLint</code> defines a professional subset of JavaScript, a stricter
language than that defined by <a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm" target="ecma">Third
Edition of the <i>ECMAScript Programming Language Standard</i></a>. The
subset is related to recommendations found in <a href="http://javascript.crockford.com/code.html" target="sun"><i>Code
Conventions for the JavaScript Programming Language</i></a>. </p>
<p>JavaScript is a sloppy language, but inside it there is an elegant, better
language. <code>JSLint</code> helps you to program in that better language
and to avoid most of the slop. JSLint will reject programs that browsers will accept because JSLint is concerned with the quality of your code and browsers are not. You should accept all of JSLint's advice.</p>
<p><code>JSLint</code> can operate on JavaScript source, HTML source, CSS source, or <a href="http://www.JSON.org/">JSON</a>
text.</p>
<h2 id=global>Global Variables</h2>
<p>JavaScript's <a href="http://yuiblog.com/blog/2006/06/01/global-domination/">biggest
problem</a> is its dependence on global variables, particularly implied
global variables. If a variable is not explicitly declared (usually with
the <code>var</code> statement), then JavaScript assumes that the variable
was global. This can mask misspelled names and other problems.</p>
<p><code>JSLint</code> expects that all variables and functions are declared
before they are used or invoked. This allows it to detect implied global
variables. It is also good practice because it makes programs easier to
read.</p>
<p>Sometimes a file is dependent on global variables and functions that
are defined elsewhere. You can identify these to <code>JSLint</code> with a <code>var</code> statement that lists the global functions and objects
that your program depends on. </p>
<p>A global declaration can look like this:</p>
<pre>var getElementByAttribute, breakCycles, hanoi;</pre>
<p>The declaration should appear near the top of the file. It must appear before the use of the variables
it declares. </p>
<p>It is necessary to use a <code>var</code> statement to declare a variable before that variable is assigned to. </p>
<p><code>JSLint</code> also recognizes a <code>/*global */</code> directive that can indicate to <code>JSLint</code> that variables used in this file were defined in other files. The comment can contain a comma separated list of names. Each name can optionally be followed by a colon and either <code>true</code> or <code>false</code>, <code>true</code> indicating that the variable may be assigned to by this file, and <code>false</code> indicating that assignment is not allowed (which is the default). The directive respects function scope.</p>
<p id=browser>Some globals can be predefined for you. Select the <i>Assume
a browser</i> (<code>browser</code>) <a href="#options">option</a> to
predefine the standard global properties that are supplied by web browsers,
such as <code>document</code> and <code>addEventListener</code>. It has the same
effect as this comment:</p>
<blockquote>
<code>/*global
clearInterval: false, clearTimeout: false, document: false, event: false, frames: false, history: false, Image: false, location: false, name: false, navigator: false, Option: false, parent: false, screen: false, setInterval: false, setTimeout: false, window: false, XMLHttpRequest: false
*/</code></blockquote>
<p>Select the
<em>Assume console, alert, ...</em>
(<code>devel</code>) <a href="#options">option</a> to predefine globals that are useful in development but that should be avoided in production, such as <code>console</code> and <code>alert</code>. It has the same
effect as this comment:</p>
<pre>/*global alert: false, confirm: false, console: false, Debug: false, opera: false, prompt: false, WSH: false */</pre>
<p id=node>Select the
<em>Assume Node.js</em>
(<code>node</code>) <a href="#options">option</a> to predefine globals that are used in the Node.js environment<code></code>. It has the same
effect as this comment:</p>
<blockquote><code>/*global Buffer: false, clearInterval: false, clearTimeout: false, console: false, exports: false, global: false, module: false, process: false, querystring: false, require: false, setInterval: false, setTimeout: false, __filename: false, __dirname: false */</code></blockquote>
<p id=rhino>Select the <i>Assume Rhino</i> (<code>rhino</code>) <a href="#options">option</a>
to predefine the global properties provided by the Rhino environment.
It has the same effect as this statement:</p>
<blockquote>
<code>/*global defineClass: false, deserialize: false, gc: false, help: false, load: false, loadClass: false, print: false, quit: false, readFile: false, readUrl: false, runCommand: false, seal: false, serialize: false, spawn: false, sync: false, toint32: false, version: false */ </code>
</blockquote>
<p id=widget>Select the <i>Assume a Yahoo Widget</i> (<code>widget</code>)
<a href="#options">option</a> to predefine the global properties provided
by the Yahoo! Widgets environment. It has the same effect as this statement:</p>
<blockquote>
<code>/*global alert: true, animator: true, appleScript: true, beep: true, bytesToUIString: true, Canvas: true, chooseColor: true, chooseFile: true, chooseFolder: true, closeWidget: true, COM: true, convertPathToHFS: true, convertPathToPlatform: true, CustomAnimation: true, escape: true, FadeAnimation: true, filesystem: true, Flash: true, focusWidget: true, form: true, FormField: true, Frame: true, HotKey: true, Image: true, include: true, isApplicationRunning: true, iTunes: true, konfabulatorVersion: true, log: true, md5: true, MenuItem: true, MoveAnimation: true, openURL: true, play: true, Point: true, popupMenu: true, preferenceGroups: true, preferences: true, print: true, prompt: true, random: true, Rectangle: true, reloadWidget: true, ResizeAnimation: true, resolvePath: true, resumeUpdates: true, RotateAnimation: true, runCommand: true, runCommandInBg: true, saveAs: true, savePreferences: true, screen: true, ScrollBar: true, showWidgetPreferences: true, sleep: true, speak: true, Style: true, suppressUpdates: true, system: true, tellWidget: true, Text: true, TextArea: true, Timer: true, unescape: true, updateNow: true, URL: true, Web: true, widget: true, Window: true, XMLDOM: true, XMLHttpRequest: true, yahooCheckLogin: true, yahooLogin: true, yahooLogout: true */</code>
</blockquote>
<p id=windows>Select the <i>Assume Windows</i> (<code>windows</code>)
<a href="#options">option</a> to predefine the global properties provided by Microsoft Windows. It has the same effect as this statement:</p>
<blockquote>
<p><code>/*global ActiveXObject: false, CScript: false, Debug: false, Enumerator: false, System: false, VBArray: false, WScript: false, WSH: false */</code></p>
</blockquote>
<h2 id=semicolon>Semicolon</h2>
<p>JavaScript uses a C-like syntax which requires the use of semicolons to delimit certain
statements. JavaScript attempts to make those semicolons optional with a semicolon
insertion mechanism. This is dangerous because it can mask errors.</p>
<p>Like C, JavaScript has <code>++</code> and <code>--</code> and <code>(</code> operators
which can be prefixes or suffixes. The disambiguation is done by the semicolon.</p>
<p>In JavaScript, a linefeed can be whitespace or it can act as a semicolon.
This replaces one ambiguity with another. </p>
<p><code>JSLint</code> expects that every statement be followed by <code>;</code> except
for <code>for</code>, <code>function</code>, <code>if</code>, <code>switch</code>, <code>try</code>, and
<code>while</code>. <code>JSLint</code> does not expect to see unnecessary semicolons or the
empty statement.</p>
<h2 id=comma>Comma</h2>
<p>The comma operator can lead to excessively tricky expressions. It can also
mask some programming errors.</p>
<p><code>JSLint</code> expects to see the comma used as a separator, but not as an
operator (except in the initialization and incrementation parts of the <code>for</code>
statement). It does not expect to see elided elements in array literals. Extra
commas should not be used. A comma should not appear after the last element
of an array literal or object literal because it can be misinterpreted by some
browsers. </p>
<h2 id=scope>Scope</h2>
<p>In many languages, a block introduces a scope. Variables introduced in
a block are not visible outside of the block.</p>
<p>In JavaScript, blocks do not introduce a scope. There is only function-scope.
A variable introduced anywhere in a function is visible everywhere in
the function. JavaScript's blocks confuse experienced programmers and
lead to errors because the familiar syntax makes a false promise.</p>
<p><code>JSLint</code> expects blocks with <code>function</code>, <code>if</code>,
<code>switch</code>, <code>while</code>, <code>for</code>, <code>do</code>,
and <code>try</code> statements and nowhere else. </p>
<p>In languages with block scope, it is usually recommended that variables
be declared at the site of first use. But because JavaScript does not
have block scope, it is wiser to declare all of a function's variables
at the top of the function. It is recommended that a single <code>var</code>
statement be used per function. This can be declined with the <code>vars</code>
<a href="#options">option</a>.</p>
<h2 id=required>Required Blocks</h2>
<p><code>JSLint</code> expects that <code>if</code>, <code>while</code>,
<code>do</code> and <code>for</code> statements will be made with blocks
<code>{</code>that is, with statements enclosed in braces<code>}</code>.</p>
<p>JavaScript allows an <code>if</code> to be written like this:</p>
<pre>if (<i>condition</i><code>)
</code><i>statement</i>;</pre>
<p>That form is known to contribute to mistakes in projects where many programmers
are working on the same code. That is why <code>JSLint</code> expects the use of
a block:</p>
<pre>if (<i>condition</i>) {
<i>statements</i>;
}</pre>
<p>Experience shows that this form is more resilient.</p>
<h2 id=expression>Expression Statements</h2>
<p>An expression statement is expected to be an assignment or a function/method
call or <code>delete</code>. All other expression statements are considered
to be errors.</p>
<h2 id="confusion">Type Confusion</h2>
<p>JSLint can do type inference. It can report cases were variables and properties are
used to house multiple types. The warning is <code>Type confusion:</code> {a} <code>and</code> {b}<code>.</code> where the {a} and {b} will be
replaced with the names of types.</p>
<p> It is usually easy to see what caused the
warning. In some cases, it can be very puzzling. In the puzzling cases, try
initializing your vars with typed values. For example, if you expect that <code>n</code> will
contain numbers, then write</p>
<pre>var n = 0;</pre>
<p>That should produce clearer warnings. </p>
<p>Type confusion is not necessarily an error, particularly in a language that
provides as much type freedom as this one does. But some inconsistencies are
errors, so type discipline might be something to consider adding to your
programming style. Also, the fastest JavaScript engines will slow down in the
presence of type confusion.
To turn off these warnings, turn on the <i>Tolerate type confusion</i> <a href="#options">option</a>. </p>
<h2 id=forin><code>for</code> <code>in</code></h2>
<p>The <code>for</code> <code>in</code> statement allows for looping through
the names of all of the properties of an object. <a href="http://yuiblog.com/blog/2006/09/26/for-in-intrigue/">Unfortunately,
it also loops through all of the properties that were inherited through
the prototype chain.</a> This has the bad side effect of serving up method
functions when the interest is in data properties. If a program is written without awareness of this situation, then it can fail.</p>
<p>The body of every <code>for</code> <code>in</code> statement should be
wrapped in an <code>if</code> statement that does filtering. It can select
for a particular type or range of values, or it can exclude functions,
or it can exclude properties from the prototype. For example,</p>
<pre>for (name in object) {
if (object.hasOwnProperty(name)) {
....
}
}</pre>
<h2 id=switch><code>switch</code></h2>
<p>A <a href="http://yuiblog.com/blog/2007/04/25/id-rather-switch-than-fight/">common
error</a> in <code>switch</code> statements is to forget to place a <code>break</code>
statement after each case, resulting in unintended fall-through. <code>JSLint</code>
expects that the statement before the next <code>case</code> or <code>default</code>
is one of these: <code>break</code>, <code>return</code>, or <code>throw</code>.
</p>
<h2 id=var><code>var</code></h2>
<p>JavaScript allows <code>var</code> definitions to occur anywhere
within a function. <code>JSLint</code> is more strict.</p>
<p><code>JSLint</code> expects that a <code>var</code> will be declared
only once, and that it will be declared before it is used.</p>
<p><code></code><code>JSLint</code> expects that a <code>function</code>
will be declared before it is used.</p>
<p><code>JSLint</code> expects that parameters will not also be declared
as vars. </p>
<p><code>JSLint</code> does not expect the <code>arguments</code> array to be declared
as a <code>var</code>.</p>
<p><code>JSLint</code> does not expect that a var will be defined in a block.
This is because JavaScript blocks do not have block scope. This can have
unexpected consequences. Define all variables at the top of the function.</p>
<h2 id=with><code>with</code></h2>
<p>The <code>with</code> statement was intended to provide a shorthand in accessing
properties in deeply nested objects. Unfortunately, it behaves <a href="http://yuiblog.com/blog/2006/04/11/with-statement-considered-harmful/">very
badly</a> when setting new properties. Never use the <code>with</code> statement. Use
a <code>var</code> instead.</p>
<p><code>JSLint</code> does not expect to see a <code>with</code> statement.</p>
<h2 id=assignment>=</h2>
<p><code>JSLint</code> does not expect to see an assignment statement in
the condition part of an <code>if</code> or <code>for</code> or <code>while</code>
<code></code> or <code>do</code> statement. This is because it is more
likely that </p>
<pre>if (a = b) {
...
}</pre>
<p>was intended to be </p>
<pre>if (a == b) {
...
}</pre>
<p>It is difficult to write correct programs while using idioms that are
hard to distinguish from obvious errors.</p>
<h2 id=eqeq>== and !=</h2>
<p>The <code>==</code> and <code>!=</code> operators do type coercion before
comparing. This is bad because it causes <code>' \t\r\n' == 0</code> to
be <code>true</code>. This can mask type errors. JSLint cannot reliably determine if == is being used correctly, so it is best to not use <code>==</code> and != and to always use the more reliable <code>===</code> and <code>!==</code> operators instead. </p>
<p align="left">If you only care that a value is <i>truthy</i> or <i>falsy</i>,
then use the short form. Instead of </p>
<pre align="left">(foo != 0)</pre>
<p align="left">just say </p>
<pre align="left">(foo)</pre>
<p align="left">and instead of</p>
<pre align="left">(foo == 0)</pre>
<p align="left"> say</p>
<pre align="left">(!foo)</pre>
<p>There is an <code>eqeq</code> <a href="#options">option</a> that allows the use of <code>==</code> and <code>!=</code>.</p>
<h2 id=labels>Labels</h2>
<p>JavaScript allows any statement to have a label, and labels have a
separate name space. <code>JSLint</code> is more strict.</p>
<p><code>JSLint</code> expects labels only on statements that interact
with <code>break</code>: <code>switch</code>, <code>while</code>,
<code>do</code>, and <code>for</code>. <code>JSLint</code> expects that labels
will be distinct from vars and parameters.</p>
<h2 id=unreachable>Unreachable Code</h2>
<p><code>JSLint</code> expects that
a <code>return</code>, <code>break</code>, <code>continue</code>,
or <code>throw</code> statement will be followed by
a <code>}</code> or <code>case</code> or <code>default</code>.</p>
<h2 id=pluses>Confusing Pluses and Minuses</h2>
<p><code>JSLint</code> expects that <code>+</code> will not be followed by
<code>+</code> or <code>++</code>, and that <code>-</code> will not be followed
by <code>-</code> or <code>--</code>. A misplaced space can turn <code>+ +</code> into <code>++</code>, an error that is difficult to see. Use parens to avoid confusion..</p>
<h2 id=inc><code>++</code> and <code>--</code></h2>
<p>The <code>++</code> <small>(increment)</small> and <code>--</code> <small>(decrement)</small>
operators have been known to contribute to bad code by encouraging excessive
trickiness. They are second only to faulty architecture in enabling to
viruses and other security menaces. Also, preincrement/postincrement confusion can produce off-by-one errors that are extremely difficult to diagnose. There is a <code>plusplus</code> <a href="#options">option</a>
that allows the use of these operators.</p>
<h2 id=bitwise>Bitwise Operators</h2>
<p>JavaScript does not have an integer type, but it does have bitwise operators.
The bitwise operators convert their operands from floating point to integers
and back, so they are not as efficient as in C or other languages. They
are rarely useful in browser applications. The similarity to the logical
operators can mask some programming errors. The <code>bitwise</code> <a href="#options">option</a>
allows the use of these operators: <code>&lt;&lt; &gt;&gt; &gt;&gt;&gt;
~ &amp; |</code>.</p>
<h2 id=evil><code>eval</code> is evil</h2>
<p>The <code>eval</code> function (and its relatives, <code>Function</code>,
<code>setTimeout</code>, and <code>setInterval</code>) provide access
to the JavaScript compiler. This is sometimes necessary, but in most cases
it indicates the presence of extremely bad coding. The <code>eval</code>
function is the most misused feature of JavaScript.</p>
<h2 id=void><code>void</code></h2>
<p>In most C-like languages, <code>void</code> is a type. In
JavaScript, <code>void</code> is a prefix operator that always
returns <code>undefined</code>. <code>JSLint</code> does not expect to
see <code>void</code> because it is confusing and not very useful.</p>
<h2 id=regexp>Regular Expressions</h2>
<p>Regular expressions are written in a terse and cryptic notation. <code>JSLint</code>
looks for problems that may cause portability problems. It also attempts
to resolve visual ambiguities by recommending explicit escapement.</p>
<p>JavaScript's syntax for regular expression literals overloads the <code>/</code>
character. To avoid ambiguity, <code>JSLint</code> expects that the character
preceding a regular expression literal is a <code>(</code> or <code>=</code>
or <code>:</code> or <code>,</code> character. </p>
<h2 id=new>Constructors and <code>new</code></h2>
<p>Constructors are functions that are designed to be used with the <code>new</code>
prefix. The <code>new</code> prefix creates a new object based on the
function's <code>prototype</code>, and binds that object to the function's
implied <code>this</code> parameter. If you neglect to use the <code>new</code>
prefix, no new object will be made and <code>this</code> will be bound
to the global object. This is a <a href="http://yuiblog.com/blog/2006/11/13/javascript-we-hardly-new-ya/">serious
mistake</a>.</p>
<p><code>JSLint</code> enforces the convention that constructor functions
be given names with initial uppercase. <code>JSLint</code> does not expect
to see a function invocation with an initial uppercase name unless it
has the <code>new</code> prefix. <code>JSLint</code> does not expect to
see the <code>new</code> prefix used with functions whose names do not
start with initial uppercase. This can be disabled with the <code>newcap</code>
<a href="#options">option</a>.</p>
<p><code>JSLint</code> does not expect to see the wrapper forms <code>new Number</code>,
<code>new String</code>, <code>new Boolean</code>. </p>
<p><code>JSLint</code> does not expect to see <code>new Object</code> (use <code>{}</code>
instead). </p>
<p><code>JSLint</code> does not expect to see <code>new Array</code> (use <code>[]</code>
instead).</p>
<h2 id=type>Type Inference</h2>
<p>Type inference is being added to JSLint. The goal is to ultimately make JSLint more helpful in spotting type inconsistencies and confusions. If you do not want this service, then select the <code>confusion</code> <a href="#options">option</a>.</p>
<h2 id=properties>Properties</h2>
<p>Since JavaScript is a loosely-typed, dynamic-object language, it is not
possible to determine at compile time if property names are spelled correctly.
<code>JSLint</code> provides some assistance with this.</p>
<p>At the bottom of its report, <code>JSLint</code> displays a <code>/*properties*/</code>
comment. It contains all of the names and string literals that were used
with dot notation, subscript notation, and object literals to name the
properties of objects. You can look through the list for misspellings. Property
names that were only used once are shown in italics. This is to make misspellings
easier to spot.</p>
<p>You can copy the <code>/*properties*/</code> comment into your script file.
<code>JSLint</code> will check the spelling of all property names against
the list. That way, you can have <code>JSLint</code> look for misspellings
for you. The directive respects function scope.</p>
<p>JSLint allows the property names to be annotated with types: <code>array</code>, <code>boolean</code>, <code>function</code>, <code>number</code>, <code>object</code>, <code>regexp</code>, <code>string</code>, or <code>*</code> (a wildcard allowing any type). A function type can be followed by another type, indicating a function's return type.</p>
<p>For example,</p>
<pre>/*properties
charAt: function string, slice: function *
*/</pre>
<h2 id=unsafe>Unsafe Characters</h2>
<p> There are characters that are handled inconsistently in browsers, and
so must be escaped when placed in strings. </p>
<pre>\u0000-\u001f
\u007f-\u009f
\u00ad
\u0600-\u0604
\u070f
\u17b4
\u17b5
\u200c-\u200f
\u2028-\u202f
\u2060-\u206f
\ufeff
\ufff0-\uffff</pre>
<h2 id=not>Not Looked For</h2>
<p><code>JSLint</code> does not do flow analysis to determine that variables are assigned
values before used. This is because variables are given a value (<code>undefined</code>)
that is a reasonable default for many applications.</p>
<p><code>JSLint</code> does not do any kind of global analysis. It does
not attempt to determine that functions used with <code>new</code> are
really constructors (<a href="#new">except by enforcing capitalization
conventions</a>), or that property names are spelled correctly (<a href="#properties">except
for matching against the <code>/*properties */</code> comment</a>).</p>
<h2 id=html>HTML</h2>
<p><code>JSLint</code> is able to handle HTML text. It can inspect the JavaScript content
contained within <code>&lt;script&gt;</code>...<code>&lt;/script&gt;</code> tags. It
also inspects the HTML content, looking for problems that are known to interfere
with JavaScript:</p>
<ul>
<li>All tag names must be in lower case.</li>
<li>All tags that can take a close tag (such as <code>&lt;/p&gt;</code>)
must have a close tag.</li>
<li>All tags are correctly nested.</li>
<li>The entity <code>&amp;lt;</code> must be used for literal <code>'&lt;'</code>.</li>
</ul>
<p><code>JSLint</code> is less anal than the sycophantic conformity demanded
by XHTML, but more strict than the popular browsers. </p>
<p><code>JSLint</code> also checks for the occurrence of<code> '&lt;/' </code>in
string literals. You should always write<code> '&lt;\/' </code>instead.
The extra backslash is ignored by the JavaScript compiler but not by the
HTML parser. Tricks like this should not be necessary, and yet they are.</p>
<p>There is a <code>cap</code> <a href="#options">option</a> that allows
use of uppercase tag names. There is also an <code>on</code> <a href="#options">option</a>
that allows the use of inline HTML event handlers.</p>
<p>There is a <code>fragment</code> <a href="#options">option</a> that can
inspect a well formed HTML fragment. If the <code>adsafe</code> <a href="#options">option</a>
is also used, then the fragment must be a <code>&lt;div&gt;</code> that
conforms to the <a href="http://www.ADsafe.org/">ADsafe</a> widget rules.</p>
<h2 id=css>CSS</h2>
<p><code>JSLint</code> can inspect CSS files. It expects the first line
of a CSS file to be </p>
<pre>@charset &quot;UTF-8&quot;;</pre>
<p>This feature is experimental. Please report any problems or limitations.
There is a <code>css</code> <a href="#options">option</a> that will tolerate
some of the non-standard-but-customary workarounds. </p>
<h2 id=options>Options</h2>
<p><code>JSLint</code> provides several options that control its operation and
its sensitivity. In the <a href="http://www.JSLint.com/">web edition</a>, the
options are selected with several checkboxes and two fields. </p>
<p>It also provides assistance in constructing <code>/*jslint*/</code>
comments.
</p>
<p>When <code>JSLINT</code> is called as a function, it accepts an <code>option</code> object
parameter that allows you to determine the subset of JavaScript that is
acceptable to you. The web page version of <code>JSLint</code> at <a href="http://www.JSLint.com/">http://www.JSLint.com/</a>
does this for you. </p>
<p>Options can also be specified within a script with a <code>/*jslint */</code>
directive:</p>
<pre>/*jslint nomen: true, debug: true,
evil: false, vars: true */</pre>
<p>An option specification starts with <code>/*jslint</code>. Notice that
there is no space before the <code>j</code>. The specification contains
a sequence of name value pairs, where the names are <code>JSLint</code>
options, and the values are <code>true</code> or <code>false</code>. The
<code>indent</code> <a href="#options">option</a> can take a number. A <code>/*jslint */</code>
comment takes precedence over the <code>option</code> object. The directive respects function scope.</p>
<table>
<tbody>
<tr>
<th>Description</th>
<th><code>option</code></th>
<th>Meaning</th>
</tr>
<tr>
<td>ADsafe</td>
<td><code>adsafe</code></td>
<td><code>true</code> if <a href="http://www.ADsafe.org/">AD<span style="color: blue;">safe</span></a>
rules should be enforced. See <a href="http://www.ADsafe.org/">http://www.ADsafe.org/</a>. <code>adsafe</code> is used with the <code>option</code> object, but not
with the <code>/*jslint */</code> comment. </td>
</tr>
<tr>
<td>Tolerate bitwise operators </td>
<td><code>bitwise</code></td>
<td><code>true</code> if bitwise operators should be allowed. <a href="#bitwise"><small>(more)</small></a></td>
</tr>
<tr>
<td>Assume a browser </td>
<td><code>browser</code></td>
<td><code>true</code> if the standard browser globals should be predefined.
<a href="#browser"><small>(more)</small></a> </td>
</tr>
<tr>
<td>Tolerate HTML case </td>
<td><code>cap</code></td>
<td><code>true</code> if uppercase HTML should be allowed.</td>
</tr>
<tr>
<td>Tolerate type confusion<br>
</td>
<td><code>confusion</code></td>
<td><code>true</code> if variables and properties are allowed to contain more than one type of value.</td>
</tr>
<tr>
<td>Tolerate <code>continue</code></td>
<td><code>continue</code></td>
<td><code>true</code> if the <code>continue</code> statement should be allowed.</td>
</tr>
<tr>
<td>Tolerate CSS workarounds</td>
<td><code>css</code></td>
<td><code>true</code> if CSS workarounds should be tolerated. <a href="#css"><small>(more)</small></a></td>
</tr>
<tr>
<td>Tolerate debugger statements</td>
<td><code>debug</code></td>
<td><code>true</code> if <code>debugger</code> statements should be
allowed. Set this option to <code>false</code> before going into production.</td>
</tr>
<tr>
<td>Assume <code>console</code>, <code>alert</code>, ...</td>
<td><code>devel</code></td>
<td><code>true</code> if browser globals that are useful in development should be
predefined. <small>(<a href="#devel">more</a>)</small></td>
</tr>
<tr>
<td>Tolerate <code>==</code> and <code>!=</code></td>
<td><code>eqeq</code></td>
<td><code>true</code> if the <code>==</code> and <code>!=</code> operators should be tolerated. <small>(<a href="#eqeq">more</a>)</small></td>
</tr>
<tr>
<td>Tolerate ES5 syntax</td>
<td><code>es5</code></td>
<td><code>true</code> if ES5 syntax should be allowed.
It is likely that programs using this option will produce syntax errors on ES3 systems.</td>
</tr>
<tr>
<td>Tolerate <code>eval</code> </td>
<td><code>evil</code></td>
<td><code>true</code> if <code>eval</code> should be allowed. <a href="#evil"><small>(more)</small></a></td>
</tr>
<tr>
<td>Tolerate unfiltered for in </td>
<td><code>forin</code></td>
<td><code>true</code> if unfiltered <code>for</code> <code>in</code>
statements should be allowed. <a href="#forin"><small>(more)</small></a></td>
</tr>
<tr>
<td>Tolerate HTML fragments </td>
<td><code>fragment</code></td>
<td><code>true</code> if HTML fragments should be allowed. <a href="#html"><small>(more)</small></a></td>
</tr>
<tr>
<td>Strict white space indentation</td>
<td><code>indent</code></td>
<td>The number of spaces used for indentation (default is 4).</td>
</tr>
<tr>
<td>Maximum number of errors</td>
<td><code>maxerr</code></td>
<td>The maximum number of warnings reported. (default is 50)</td>
</tr>
<tr>
<td>Maximum line length</td>
<td><code>maxlen</code></td>
<td>The maximum number of characters in a line.</td>
</tr>
<tr>
<td>Tolerate uncapitalized constructors</td>
<td><code>newcap</code></td>
<td><code>true</code> if Initial Caps with constructor
functions is optional. <a href="#new"><small>(more)</small></a></td>
</tr>
<tr>
<td>Assume Node.js</td>
<td><code>node</code></td>
<td><code>true</code> if Node.js globals should be predefined. <a href="#node"><small>(more)</small></a></td>
</tr>
<tr>
<td>Tolerate dangling _ in identifiers </td>
<td><code>nomen</code></td>
<td><code>true</code> if names should not be checked for initial or trailing underbars.</td>
</tr>
<tr>
<td>Tolerate HTML event handlers </td>
<td><code>on</code></td>
<td><code>true</code> if HTML event handlers should be allowed. <a href="#html"><small>(more)</small></a></td>
</tr>
<tr>
<td>Stop on first error </td>
<td><code>passfail</code></td>
<td><code>true</code> if the scan should stop on first error.</td>
</tr>
<tr>
<td>Tolerate <code>++</code> and <code>--</code> </td>
<td><code>plusplus</code></td>
<td><code>true</code> if <code>++</code> and <code>--</code> should
be allowed. <a href="#inc"><small>(more)</small></a></td>
</tr>
<tr>
<td>Predefined <small>( , separated)</small></td>
<td><code>predef</code></td>
<td>An array of strings, the names of predefined global variables, or an object whose keys are global variable names, and whose values are booleans that determine if each variable is assignable (also see <a href="#global">global</a>). <code>predef</code> is used with the <code>option</code> object, but not
with the <code>/*jslint */</code> comment. You can also use the <code>var</code>
statement to declare global variables in a script file.</td>
</tr>
<tr>
<td>Tolerate <code>.</code> and <code>[^</code>...<code>]</code>. in /RegExp/ </td>
<td><code>regexp</code></td>
<td><code>true</code> if <code>.</code> and <code>[^</code>...<code>]</code> should be allowed in RegExp
literals. They match more material than might be expected, allowing attackers to confuse applications. These forms should not be used when validating in secure applications. </td>
</tr>
<tr>
<td>Assume Rhino </td>
<td><code>rhino</code></td>
<td><code>true</code> if the <a href="http://www.mozilla.org/rhino/">Rhino</a>
environment globals should be predefined. <a href="#rhino"><small>(more)</small></a></td>
</tr>
<tr>
<td>Safe Subset </td>
<td><code>safe</code></td>
<td><code>true</code> if the safe subset rules are enforced. These rules
are used by <a href="http://www.ADsafe.org/">ADsafe</a>. It enforces
the safe subset rules but not the widget structure rules. <code>safe</code> is used with the <code>option</code> object, but not
with the <code>/*jslint */</code> comment. </td>
</tr>
<tr>
<td> Tolerate missing&nbsp;<code>'use strict'</code>&nbsp;pragma </td>
<td><code>sloppy</code></td>
<td><code>true</code> if the ES5 <code><a href="http://www.yuiblog.com/blog/2010/12/14/strict-mode-is-coming-to-town/">'use strict';</a></code> pragma
is not required. Do not use this pragma unless you know what you are doing.</td>
</tr>
<tr>
<td>Tolerate inefficient subscripting<br>
</td>
<td><code>sub</code></td>
<td><code>true</code> if subscript notation may be used for expressions
better expressed in dot notation.</td>
</tr>
<tr>
<td> Tolerate misordered definitions </td>
<td><code>undef</code></td>
<td><code>true</code> if variables and functions need not be declared before used. <a href="#undefined"><small>(more)</small></a></td>
</tr>
<tr>
<td> Tolerate unused parameters</td>
<td><code>unparam</code></td>
<td><code>true</code> if warnings should not be given for unused parameters.</td>
</tr>
<tr>
<td>Tolerate many&nbsp;<tt>var</tt>&nbsp;statements per function</td>
<td><code>vars</code></td>
<td><code>true</code> if multiple <code>var</code> statement per function
should be allowed. <a href="#scope"><small>(more)</small></a></td>
</tr>
<tr>
<td> Tolerate messy white space</td>
<td><code>white</code></td>
<td><code>true</code> if strict whitespace rules should be ignored.</td>
</tr>
<tr>
<td>Assume a Yahoo Widget </td>
<td><code>widget</code></td>
<td><code>true</code> if the <a href="http://widgets.yahoo.com/gallery/view.php?widget=37484">Yahoo
Widgets</a> globals should be predefined. <a href="#widget"><small>(more)</small></a></td>
</tr>
<tr>
<td>Assume Windows</td>
<td><code>windows</code></td>
<td><code>true</code> if the Windows globals should be predefined. <a href="#windows"><small>(more)</small></a></td>
</tr>
</tbody>
</table>
<h2 id=report>Report</h2>
<p>If <code>JSLint</code> is able to complete its scan, it generates a function
report. It lists for each function:</p>
<ul>
<li>The line number on which it starts.</li>
<li>Its name. In the case of anonymous functions, <code>JSLint</code>
will 'guess' the name.</li>
<li>The parameters.</li>
<li><i>Closure</i>: The variables and parameters that are declared in
the function that are used by its inner functions.</li>
<li><i>Variables</i>: The variables that are declared in the function
that are used only by the function.</li>
<li><i>Exceptions</i>: The variables that are declared by try statements.</li>
<li><i>Unused</i>: The variables that are declared in the function that
are not used. This may be an indication of an error.</li>
<li><i>Outer</i>: Variables used by this function that are declared in
another function.</li>
<li><i>Global</i>: Global variables that are used by this function. Keep
these to a minimum.</li>
<li><i>Label</i>: Statement labels that are used by this function.</li>
</ul>
<p>The report will also include a list of all of the <a href="#properties">property
names</a> that were used. There is a <a href="msgs.html">list of <code>JSLint</code>
messages</a>.</p>
<h2 id=feedback>Feedback</h2>
<p>Please let me know if <code>JSLint</code> is useful for you. Is it too
strict? Is there a check or a report that could help you to improve the
quality of your programs?
<a href="mailto:douglas@crockford.com">douglas@crockford.com</a>.
But please don't ask me to dumb <code>JSLint</code> down or to make it more
forgiving of bad practices. You would only be disappointed.</p>
<p>I intend to continue to adapt <code>JSLint</code> based on your comments.
Keep watching for improvements. Updates are announced at
<a href="http://tech.groups.yahoo.com/group/jslint_com/">http://tech.groups.yahoo.com/group/jslint_com/</a>. </p>
<h2 id=try>Try it</h2>
<p><a href="http://www.JSLint.com" target="_blank">Try it.</a> Paste your script
into the window and click the
<a href="http://www.JSLint.com" target=jslint><input type="button" value="JSLint"></a>
button. The analysis is done by a script running on your machine.
Your script is not sent over the network. You can set the <a href="#options">options</a> used. </p>
<p>
JSLint is written entirely in JavaScript, so it can run anywhere that JavaScript can run. See for example <a href="http://tech.groups.yahoo.com/group/jslint_com/database?method=reportRows&tbl=1">http://tech.groups.yahoo.com/group/jslint_com/database?method=reportRows&amp;tbl=1</a>.</p>
<h2 id=implementation>Implementation</h2>
<p><code>JSLint</code> uses a <a href="http://javascript.crockford.com/tdop/tdop.html">Pratt
Parser (Top Down Operator Precedence)</a>. It is written in JavaScript.
The full source code is available: <a href="https://github.com/douglascrockford/JSLint">https://github.com/douglascrockford/JSLint</a>.</p>
<a href="http://www.JSLint.com/"><img src="jslintpill.gif" width="36" height="17" border="0"></a>
<a href="http://www.ADsafe.org/"><img src="adsafepill.gif" width="36" height="17" border="0"></a>
<a href="http://www.JSON.org/"><img src="jsonpill.gif" width="36" height="17" border="0"></a>
</body>
</html>