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<h1>Errata<div style="font-size: 70%"><a class="subtlelink" href="index.html">Eloquent JavaScript</a></div></h2>

<p>These are the known mistakes in the <strong>second edition</strong>

of the book. For errata in the first edition,

see <a href="http://eloquentjavascript.net/1st_edition/errata.html">this

page</a>. To report a problem that is not listed

here, <a href="mailto:marijnh@gmail.com">send me an email</a>.</p>

<p>Issues whose section title is followed by a superscript ¹ were

fixed after the first print of the book, and will not be present in

later prints. Those followed by ² were fixed in the third print.</p>

<h2>Introduction</h2>

<p><strong>Page 4</strong> (Why Language Matters¹): The sentence “You

can probably imagine how how tedious…” duplicates the

word <em>how</em>.</p>

<h2>Chapter 2</h2>

<p><strong>Page 32</strong> (while and do Loops²): The <code>var

name</code> example unintentionally exits the loop when the dialog is

canceled, because browsers have a built-in global

variable <code>name</code> whose values are implicitly converted to

strings.</p>

<h2>Chapter 9</h2>

<p><strong>Page 157</strong> (Repeating Parts of a Pattern): The

paragraph at the top of the page claims that <code>{,5}</code> is equivalent to

<code>{0,5}</code> in a regular expression. This is not the case (you

have to include the zero).</p>

<p><strong>Page 159</strong> (The Date Type¹):

The <code>findDate</code> function produces the wrong months. The

second argument given to <code>new Date</code> should

be <code>Number(match[2]) - 1</code>, subtracting one to compensate

for the fact that months start at zero in this interface.</p>

<p><strong>Page 162</strong> (Backtracking²): The regular expression

should have another <code>+</code> sign after the <code>[\da-f]</code>

group to match what it is described as matching. The diagram for the

expression is similarly missing an arrow looping back around the

corresponding box.</p>

<h2>Chapter 10</h2>

<p><strong>Page 185</strong> (Slow-Loading Modules¹): In the code

snippet for <code>define</code>, the second use of

the <code>every</code> method is incorrect. The call should be

to <code>myMod.onLoad.forEach</code> instead.</p>

<h2>Chapter 11</h2>

<p><strong>Page 192</strong> (Parsing¹): The example Egg program has

its parentheses distributed incorrectly. One closing parentheses from

the second line should be moved to the end of the last line.</p>

<h2>Chapter 12</h2>

<p><strong>Page 209</strong> (The Web²): In the third paragraph I claim

that the U in “URL” stands for <em>Universal</em>, whereas it actually

stands for <em>Uniform</em>.</p>

<h2>Chapter 14</h2>

<p><strong>Page 242</strong> (Mouse Motion¹): The example

uses <code>event.which</code> to detect mouse button release. This

only works in Chrome and Safari. See

the <a href="14_event.html#c_xBQPHox4ts">updated code</a>

and <a href="14_event.html#p_fndkFYbayW">comment</a> for a better

way.</p>

<h2>Chapter 16</h2>

<p><strong>Page 281</strong> (Curves¹): The text refers to

the <code>bezierCurve</code> method. This method is actually

called <code>bezierCurveTo</code> (as in the example code).</p>

<p><strong>Page 282</strong> (Curves¹): Where it says the picture shows

a line from the left of the circle to the left of the quarter circle,

it should definitely say <em>right</em> in both instances.</p>

<h2>Chapter 17</h2>

<p><strong>Page 312</strong> (Summary¹): The code example uses

the <code>statusCode</code> property. This does not exist, since the

property is actually called <code>status</code>.</p>

<h2>Chapter 18</h2>

<p><strong>Page 316</strong> (Fields²): The <code>checked</code>

attribute in the <code>file</code> field at the bottom of the example

doesn't mean anything, and should not be there.</p>

<p><strong>Page 327</strong> (Summary¹): “When the user has selected

a <em>field</em>” should be “When the user has selected

a <em>file</em>”.

<h2>Chapter 21</h2>

<p><strong>Page 377</strong> (Long-Polling Support): In the second

paragraph the <code>changesSince</code> parameter is incorrectly

referred to as <code>changeSince</code> (singular).</p>