Javascript [Electronic resources] : The Definitive Guide (4th Edition) نسخه متنی

1.1 JavaScript Myths

JavaScript is the subject of a fair bit
of misinformation and confusion. Before proceeding any further with
our exploration of JavaScript, it is important that we debunk some
common and persistent myths about the language.

1.1.1 JavaScript Is Not Java

One of the most common
misconceptions about JavaScript is that it is a simplified version of
Java, the programming language from Sun Microsystems. Other than an
incomplete syntactic resemblance and the fact that both Java and
JavaScript can provide executable content in web browsers, the two
languages are entirely unrelated. The similarity of names is purely a
marketing ploy (the language was originally called LiveScript; its
name was changed to JavaScript at the last minute).

JavaScript and Java do, however, make a good team. The two languages
have different sets of capabilities. JavaScript can control browser
behavior and content but cannot draw graphics or perform networking.
Java has no control over the browser as a whole but can do graphics,
networking, and multithreading. Client-side JavaScript can interact
with and control Java applets embedded in a web page, and, in this
sense, JavaScript really can script Java (see Chapter 22 for details).

1.1.2 JavaScript Is Not Simple

JavaScript is touted as a scripting
language instead of a programming language, the implication being
that scripting languages are simpler, that they are programming
languages for non-programmers. Indeed, JavaScript appears at first
glance to be a fairly simple language, perhaps of the same complexity
as BASIC. JavaScript does have a number of features designed to make
it more forgiving and easier to use for new and unsophisticated
programmers. Non-programmers can use JavaScript for limited,
cookbook-style programming tasks.

Beneath its thin veneer of simplicity, however, JavaScript is a
full-featured programming language, as complex as any and more
complex than some. Programmers who attempt to use JavaScript for
nontrivial tasks often find the process frustrating if they do not
have a solid understanding of the language. This book documents
JavaScript comprehensively, so you can develop a sophisticated
understanding of the language.