JavaScript for ABAP Programmers Chapter 1 - Introduction to JavaScript

1. JavaScript for ABAP Programmers
Introduction
Chris Whealy / The RIG

2. JavaScript’s Name – And the Resulting Confusion…
JavaScript was first developed by Brendan Eich at Netscape in 1995 (in 10 days). Originally this new
scripting language was called “Mocha”.
When Netscape Navigator 2.0 was shipped in September 1995, the language was renamed to
“LiveScript”.
However, when Netscape Navigator 2.0B3 was released on December 4th, 1995, Netscape made a
joint announcement with Sun Microsystems to the effect that Netscape’s new scripting language would
complement Sun Microsystem’s new Web application language Java; therefore, the new scripting
language would be called “JavaScript” – and this has caused no end of confusion ever since…
The bottom line is simply this…
JavaScript is NOT Java!
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3. JavaScript’s Linguistic Heritage
Over the course of the language’s development, various conceptual elements have been borrowed
from other languages to form what is now called JavaScript.
JavaScript
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4. JavaScript’s Linguistic Heritage
Over the course of the language’s development, various conceptual elements have been borrowed
from other languages to form what is now called JavaScript.
JavaScript
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5. JavaScript’s Linguistic Heritage
Over the course of the language’s development, various conceptual elements have been borrowed
from other languages to form what is now called JavaScript.
Scheme
JavaScript
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6. JavaScript’s Linguistic Heritage
Over the course of the language’s development, various conceptual elements have been borrowed
from other languages to form what is now called JavaScript.
Scheme
JavaScript
Perl
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7. JavaScript Standards
JavaScript was standardised by the European Computer Manufacturer’s Association (ECMA) in 1997.
JavaScript used in browsers is now considered to be only one implementation of the ECMA-262
specification.
Edition
Date
1 June 1997
2 June 1998
3 December 1999
4 Abandoned
5 December 2009
5.1 June 2011
6 (Harmony) Work in progress
7 Work in progress
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8. JavaScript Runtime Engines
In order to execute a JavaScript program, a JavaScript Engine is needed.
Multiple implementations of JavaScript engines are available, with the most widely used being:
JavaScript Engine
Rhino (Mozilla)
SpiderMonkey (Mozilla)
Chakra (Microsoft)
V8 (Google)
Nitro (Apple)
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9. JavaScript Runtime: Client Side Implementations
Modern JavaScript engines have been designed to run either from within a web browser or as stand
alone, server-side execution engines.
Browser
JavaScript Engine
Mozilla Firefox
SpiderMonkey (Mozilla)
Microsoft Internet Explorer
Chakra (Microsoft)
Google Chrome
V8 (Google)
Apple Safari
Nitro (Apple)
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10. JavaScript Runtime: Server Side Implementations
There are multiple server-side implementations of JavaScript, many of which are based on Mozilla
Rhino (Java based). When speed is required however, Mozilla SpiderMonkey or the Google V8
engine are used instead.
Server Side Implementation
JavaScript Engine
SpiderMonkey (Mozilla)
HANA XSJS
Accessible via
Chakra (Microsoft)
V8 (Google)
Nitro (Apple)
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11. In A Nutshell – The Main Differences Between ABAP & JavaScript
Understanding the differences between ABAP and JavaScript is fundamental to transferring your
existing programming skills into JavaScript. Some of the main differences are as follows:
ABAP
JavaScript
Strongly typed
Weakly typed
Syntax similar to COBOL
Syntax derived from Java (and C)
Block scope
Lexical scope
No equivalent concept
Functions are 1st class citizens
OO using class based inheritance
OO using referential inheritance
Imperative programming
Imperative or Functional programming
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