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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Technical Documentation - Tanimara's JS</title>
<link rel="stylesheet" href="styles.css" />
</head>
<body>
<nav id="navbar">
<header>JS Documentation</header>
<ul>
<li>
<a class="nav-link" href="#Introduction">Introduction</a>
</li>
<li>
<a class="nav-link" href="#JavaScript_and_Java"
>JavaScript and Java</a
>
</li>
<li>
<a class="nav-link" href="#Hello_world">Hello World</a>
</li>
<li>
<a class="nav-link" href="#Variables">Variables</a>
</li>
<li>
<a class="nav-link" href="#Declaring_variables"
>Declaring Variables</a
>
</li>
<li>
<a class="nav-link" href="#Variable_scope">Variable Scope</a>
</li>
<li>
<a class="nav-link" href="#Data_types">Data Types</a>
</li>
</ul>
</nav>
<main id="main-doc">
<section class="main-section" id="Introduction">
<header>Introduction</header>
<article>
<p>
JavaScript is a cross-platform, object-oriented scripting language.
It is a small and lightweight language. Inside a host environment
(for example, a web browser), JavaScript can be connected to the
objects of its environment to provide programmatic control over
them.
</p>
<p>
JavaScript contains a standard library of objects, such as Array,
Date, and Math, and a core set of language elements such as
operators, control structures, and statements. Core JavaScript can
be extended for a variety of purposes by supplementing it with
additional objects; for example:
</p>
<ul>
<li>
Client-side JavaScript extends the core language by supplying
objects to control a browser and its Document Object Model (DOM).
For example, client-side extensions allow an application to place
elements on an HTML form and respond to user events such as mouse
clicks, form input, and page navigation.
</li>
<li>
Server-side JavaScript extends the core language by supplying
objects relevant to running JavaScript on a server. For example,
server-side extensions allow an application to communicate with a
database, provide continuity of information from one invocation to
another of the application, or perform file manipulations on a
server.
</li>
</ul>
</article>
</section>
<section class="main-section" id="JavaScript_and_Java">
<header>JavaScript and Java</header>
<article>
<p>
JavaScript and Java are similar in some ways but fundamentally
different in some others. The JavaScript language resembles Java but
does not have Java's static typing and strong type checking.
JavaScript follows most Java expression syntax, naming conventions
and basic control-flow constructs which was the reason why it was
renamed from LiveScript to JavaScript.
</p>
<p>
In contrast to Java's compile-time system of classes built by
declarations, JavaScript supports a runtime system based on a small
number of data types representing numeric, Boolean, and string
values. JavaScript has a prototype-based object model instead of the
more common class-based object model. The prototype-based model
provides dynamic inheritance; that is, what is inherited can vary
for individual objects. JavaScript also supports functions without
any special declarative requirements. Functions can be properties of
objects, executing as loosely typed methods.
</p>
<p>
JavaScript is a very free-form language compared to Java. You do not
have to declare all variables, classes, and methods. You do not have
to be concerned with whether methods are public, private, or
protected, and you do not have to implement interfaces. Variables,
parameters, and function return types are not explicitly typed.
</p>
</article>
</section>
<section class="main-section" id="Hello_world">
<header>Hello world</header>
<article>
To get started with writing JavaScript, open your console on the web
browser of your choice and write your first "Hello world" JavaScript
code:
<code>
function greetMe(yourName) { alert("Hello " + yourName); }
greetMe("World");
</code>
Watch what the code does in your browser!
</article>
</section>
<section class="main-section" id="Variables">
<header>Variables</header>
<p>
You use variables as symbolic names for values in your application.
The names of variables, called identifiers, conform to certain rules.
</p>
<p>
A JavaScript identifier must start with a letter, underscore (_), or
dollar sign ($); subsequent characters can also be digits (0-9).
Because JavaScript is case sensitive, letters include the characters
"A" through "Z" (uppercase) and the characters "a" through "z"
(lowercase).
</p>
<p>
You can use ISO 8859-1 or Unicode letters such as å and ü in
identifiers. You can also use the Unicode escape sequences as
characters in identifiers. Some examples of legal names are
Letter_hits, temp88, and _age.
</p>
</section>
<section class="main-section" id="Declaring_variables">
<header>Declaring variables</header>
<p>You can declare a variable in three ways:</p>
<p>With the keyword var. For example,</p>
<code>var x = 78.</code>
<p>
This syntax can be used to declare both local and global variables.
</p>
<p>By simply assigning it a value. For example,</p>
<code>x = 78.</code>
<p>
This always declares a global variable. It generates a strict
JavaScript warning. You shouldn't use this variant.
</p>
<p>With the keyword let. For example,</p>
<code>let y = 95.</code>
<p>This syntax can be used to declare a block scope local variable.</p>
</section>
<section class="main-section" id="Variable_scope">
<header>Variable scope</header>
<p>
When you declare a variable outside of any function, it is called a
global variable, because it is available to any other code in the
current document. When you declare a variable within a function, it is
called a local variable, because it is available only within that
function.
</p>
<p>
JavaScript before ECMAScript 2015 does not have block statement scope;
rather, a variable declared within a block is local to the function
(or global scope) that the block resides within. For example the
following code will log 5, because the scope of x is the function (or
global context) within which x is declared, not the block, which in
this case is an if statement.
</p>
<code> if (true) { var x = 10; } console.log(x); // 10</code>
<p>
This behavior changes, when using the let declaration introduced in
ECMAScript 2015.
</p>
<code>
if (true) { let y = 5; } console.log(y); // ReferenceError: y is not
defined
</code>
</section>
<section class="main-section" id="Data_types">
<header>Data types</header>
<p>The latest ECMAScript standard defines seven data types:</p>
<ul>
<li>Six data types that are primitives:</li>
<ul>
<li>Boolean. true and false.</li>
<li>
null. A special keyword denoting a null value. Because JavaScript
is case-sensitive, null is not the same as Null, NULL, or any
other variant.
</li>
<li>undefined. A top-level property whose value is undefined.</li>
<li>Number. 78 or 3.14159.</li>
<li>String. "Hello"</li>
<li>
Symbol (new in ECMAScript 2015). A data type whose instances are
unique and immutable.
</li>
</ul>
<li>and Object.</li>
</ul>
<p>
Although these data types are a relatively small amount, they enable
you to perform useful functions with your applications. Objects and
functions are the other fundamental elements in the language. You can
think of objects as named containers for values, and functions as
procedures that your application can perform.
</p>
</section>
</main>
</body>
</html>