Skip to content

Commit 2b636f7

Browse files
douglascrockforddouglascrockford
committed
First Commit
1 parent 59a80ff commit 2b636f7

36 files changed

+6729
-0
lines changed

‎A.html

+541
Large diffs are not rendered by default.

‎B.html

+198
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,198 @@
1+
<html>
2+
<head>
3+
<title>The JavaScript Encyclopedia: B</title>
4+
<link rel="stylesheet" href="encyclopedia.css" type="text/css">
5+
</head>
6+
7+
<body>
8+
<h1>B</h1>
9+
10+
<h2 id="bind">bind</h2>
11+
<h3 id="bind function prototype function"><code>bind</code> <code>function</code> prototype function</h3>
12+
<p>Blah.</p>
13+
<p class="es3">The <code>bind</code> function is not available in <a href="E.html#ES3">ES3</a>.</p>
14+
15+
<h2 id="bitwise operator">bitwise operator</h2>
16+
<p>A bitwise operator treats a <a href="N.html#number">number</a> as a 32 bit 2's complement signed integer. The bitwise operators
17+
are</p>
18+
<ul>
19+
<li><a href="special.html#ampersand%20infix%20operator"><code>&amp;</code> infix
20+
operator</a> <dfn>bitwise and</dfn></li>
21+
<li><a href="special.html#bar%20infix%20operator"><code>|</code> infix operator</a>
22+
<dfn>bitwise or</dfn></li>
23+
<li><a href="special.html#caret%20infix%20operator"><code>^</code> infix operator</a>
24+
<dfn>bitwise exclusive or</dfn></li>
25+
<li><a href="special.html#ampersandlt;&lt;%20infix%20operator"><code>&lt;&lt;</code>
26+
infix operator</a> <dfn>bitwise left shift</dfn></li>
27+
<li><a href="special.html#greater>%20infix%20operator"><code>&gt;&gt;</code>
28+
infix operator</a> <dfn>bitwise signed right shift</dfn></li>
29+
<li><a href="special.html#greater>>%20infix%20operator"><code>&gt;&gt;&gt;</code>
30+
infix operator</a> <dfn>bitwise unsigned right shift</dfn></li>
31+
<li><a href="special.html#tilde%20infix%20operator"><code>~</code> prefix
32+
operator</a> <dfn>bitwise not</dfn></li>
33+
</ul>
34+
<p>These operators allow access to some of the primitive operations of CPUs. They all treat <a href="N.html#NaN"><code>NaN</code></a>, <a href="N.html#null"><code>null</code></a>, and <a href="U.html#undefined"><code>undefined</code></a> as <code>0</code>. Also see <a href="I.html#integer">integer</a>.</p>
35+
36+
<p>Example:</p>
37+
<pre>var raw_base64 = (function (alphabet) {
38+
39+
// The raw_base64 object contains two methods, encode and decode, that convert
40+
// strings to base64 and back, as specified in Multipurpose Internet Mail
41+
// Extensions (MIME) Section 6.8. URL: http://www.ietf.org/rfc/rfc2045.txt.
42+
// The standard also requires padding with = and the breaking and joining of
43+
// lines no longer than 76 characters. We are not concerned with that. All
44+
// we are doing here is encoding groups of 3 8-bit characters as 4 7-bit
45+
// characters.
46+
47+
// The original motivation for doing this was to avoid data interchange
48+
// problems caused by poor architectural choices in some mid 20th century
49+
// operating systems. These workarounds became standards that are still in
50+
// force, decades after solution of the root problem. Once something gets into
51+
// a standard, it can take generations to get rid of it.
52+
53+
// We will encode using an alphabet of 64 characters: 26 upper case letters,
54+
// 26 lower case letters, 10 digits, and two special characters. For efficent
55+
// decoding, we will invert the alphabet ('ABC...9+/') into an object, producing
56+
// {
57+
// A: 0,
58+
// B: 1,
59+
// C: 2,
60+
// ...
61+
// '9': 61,
62+
// '+': 62,
63+
// '/': 63
64+
// }
65+
66+
var alphabet =
67+
'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/',
68+
tebahpla = {};
69+
alphabet.split('').forEach(function (value, index) {
70+
tebahpla[value] = index;
71+
});
72+
73+
// Return the object containing the encode and decode methods.
74+
75+
return {
76+
encode: function (unencoded) {
77+
var i,
78+
length = unencoded.length,
79+
result = [],
80+
in0,
81+
in1,
82+
in2;
83+
84+
for (i = 0; i &lt; length; i += 3) {
85+
86+
// Get the next three character codes.
87+
88+
in0 = unencoded.charCodeAt(i);
89+
in1 = unencoded.charCodeAt(i + 1);
90+
in2 = unencoded.charCodeAt(i + 2);
91+
92+
// Redistribute 3 sets of 8 bits into 4 sets of 6 bits.
93+
94+
// in: abcdefgh ijklmnop qrstuvwx
95+
// out: 00abcdef 00ghijkl 00mnopqr 00stuvwx
96+
97+
// This involves shifting bits into a new positions, using &amp; (and) to mask off
98+
// some bits, and using | (or) to combine.
99+
100+
// Translate the 6-bit values into symbols of the alphabet and push them into
101+
// the results.
102+
103+
result.push(alphabet[in0 &gt;&gt; 2]);
104+
result.push(alphabet[((in0 &amp; 3) &lt;&lt; 4) | (in1 &gt;&gt; 4)]);
105+
106+
// We only output the third character if in1 was present.
107+
108+
if (!isNaN(in1)) {
109+
result.push(alphabet[((in1 &amp; 15) &lt;&lt; 2) | (in2 &gt;&gt; 6)]);
110+
111+
// And we only output the fourth character if in2 was present.
112+
113+
if (!isNaN(in2)) {
114+
result.push(alphabet[in2 &amp; 63]);
115+
}
116+
}
117+
}
118+
119+
// Return the result string.
120+
121+
return result.join('');
122+
},
123+
124+
decode: function (encoded) {
125+
var i,
126+
length = encoded.length - 1,
127+
result = [],
128+
in0,
129+
in1,
130+
in2,
131+
in3;
132+
for (i = 0; i &lt; length; i += 4) {
133+
134+
// Get the next four character codes.
135+
136+
in0 = tebahpla[encoded.charAt(i)];
137+
in1 = tebahpla[encoded.charAt(i + 1)];
138+
in2 = tebahpla[encoded.charAt(i + 2)];
139+
in3 = tebahpla[encoded.charAt(i + 3)];
140+
141+
// Redistribute 4 sets of 6 bits into 3 sets of 8 bits.
142+
143+
// in: 00abcdef 00ghijkl 00mnopqr 00stuvwx
144+
// out: abcdefgh ijklmnop qrstuvwx
145+
146+
// Combine bits from in0 and in1 to produce the first character code.
147+
// Convert the code into a character, and push it onto the result.
148+
149+
result.push(String.fromCharCode((in0 &lt;&lt; 2) | (in1 &gt;&gt; 4)));
150+
151+
// We only output the second character if in2 was present.
152+
153+
if (in2 !== undefined) {
154+
result.push(String.fromCharCode(((in1 &amp; 15) &lt;&lt; 4) | (in2 &gt;&gt; 2)));
155+
156+
// And we only output the third character if in3 was present.
157+
158+
if (in3 !== undefined) {
159+
result.push(String.fromCharCode(((in2 &amp; 3) &lt;&lt; 6) | in3));
160+
}
161+
}
162+
}
163+
164+
// Return the result string.
165+
166+
return result.join('');
167+
}
168+
};
169+
}());</pre>
170+
<h2 id="blink">blink</h2>
171+
<p><blink>Blah.</blink></p>
172+
<h2 id="block">block</h2>
173+
<p>A block is a compound <a href="S.html#statement">statement</a> that can occur anywhere that a <a href="S.html#statement">statement</a> can occur. It begins with a <a href="special.html#leftbrace"><code>{</code> <dfn>left curly brace</dfn></a> and ends with a <a href="special.html#}"><code>}</code> <dfn>right curly brace</dfn></a>, and between the two curly braces there are zero or more statements. Blocks are commonly used as parts of other statements, such as <a href="I.html#if statement"><code>if</code> statement</a> and <a href="W.html#while statement"><code>while</code> statement</a>.</p>
174+
<p>A brace does not create a new <a href="S.html#scope">scope</a>. Only a function has <a href="S.html#scope">scope</a>. In many other languages, a block does create a <a href="S.html#scope">scope</a>, so that a <a href="V.html#variable">variable</a> that is declared inside of a block is not visible outside of the block. That does not happen in the language, which is why it is unwise to declare a <a href="variable">variable</a> in a block.</p>
175+
<h2>body</h2>
176+
<p>See <a href="F.html#function body">function body</a>.</p>
177+
178+
<h2 id="boolean">boolean</h2>
179+
<p>The boolean type is named after the mathematician George Boole. The boolean type contains exactly two values: <a href="T.html#true"><code>true</code></a> and <a href="F.html#false"><code>false</code></a>. The <a href="T.html#typeof prefix operator"><code>typeof</code> prefix operator</a> returns <code>'boolean'</code> when its operand is a boolean. A boolean value is produced by a <a href="R.html#relational operator">relational operator</a>.</p>
180+
<h3 id="Boolean global function"><code>Boolean</code> global function</h3>
181+
<p>The <code>Boolean(</code><var>value</var><code>)</code> <a href="G.html#global function">global function</a>, when called as function, evaluates its parameter. If the value was <a href="T.html#truthy">truthy</a>, it returns <a href="T.html#true"><code>true</code></a>. If the value was <a href="F.html#falsy">falsy</a>, it returns <a href="F.html#false"><code>false</code></a>. </p>
182+
<h3 id="boolean literal">boolean literal</h3>
183+
<p>There are two boolean literals, representing the two boolean values: <a href="T.html#true"><code>true</code></a> and <a href="F.html#false"><code>false</code></a>.</p>
184+
<h2 id="boolish">boolish</h2>
185+
<p>Every value in JavaScript is boolish in that it is either <a href="T.html#truthy">truthy</a> or <a href="F.html#falsy">falsy</a>. The <a href="#boolean">boolean</a> type contains only the <code>true</code> and <code>false</code> values, but the boolish type includes all values.</p>
186+
<h2 id="bound variable">bound variable</h2>
187+
<p>Blah.</p>
188+
<h2>brace</h2>
189+
<p>See <a href="special.html#leftbrace"><code>{</code> <dfn>left curly brace</dfn></a> and <a href="special.html#}"><code>}</code> <dfn>right curly brace</dfn></a>.</p>
190+
<h2>bracket</h2>
191+
<p>See <a href="special.html#leftbracket"><code>[</code> <dfn>left bracket
192+
</dfn></a> and <a href="special.html#rightbracket"><code>]</code> <dfn>right bracket</dfn></a>.</p>
193+
194+
<h2 id="break">break <a href="R.html#reserved word"><strong>reserved word</strong></a></h2>
195+
<h3 id="break statement"><code>break</code> statement</h3>
196+
<p>Blah.</p>
197+
</body>
198+
</html>

0 commit comments

Comments
 (0)