Editing JavaScript/JScript (section)

==Introduction==
Netscape originally developed a scripting language for use in its browsers, calling it LiveScript. For marketing reasons they renamed the scripting language to JavaScript. Microsoft implemented its own version of JavaScript and called it JScript.
Netscape, Microsoft and others started standardizing the scripting language, using the ECMA standardizing organisation (http://www.ecma.ch) for that. Thus the language standard is now  called ECMA Script.
Note that this standard is only about the core language, with data and objects like numbers, strings, booleans, Object, Array, Function, Date, Math, but NOT about application specific objects like browser specific objects (document, window, links, images etc)
* 1999: ES3
* 2009: ES5
* 2015: ES6 (class, constructor, extends, super, ...)
* 2016: ES7
* 2017: ES8

The core features of Netscape's JavaScript and Microsoft's JScript are pretty much compliant with the ECMA Script standard, but the application specific objects like the browser DOM (Document Object Model) and the server object model differ, slightly less with time. Für die folgende Beschreibung wird '''JS''' als Synonym zu JavaScript und JScript verwendet.
JS-Programme werden wahlweise direkt in der HTML-Datei oder in separaten Dateien notiert. Sie werden nicht - wie etwa Java-Programme - compiliert, sondern als Quelltext zur Laufzeit interpretiert, also ähnlich wie Batchdateien bzw. Shellscripts. Dazu besitzen moderne WWW-Browser wie Netscape oder Microsoft Internet Explorer entsprechende Interpreter-Software.

* JS is an interpreted, object-based scripting language. JavaScript has a prototype-based, object-oriented programming model. It creates objects using other objects as blueprints and to implement inheritance it manipulates what’s called a prototype chain.Although it has fewer capabilities than full-fledged object-oriented languages like C++ and Java, JS is more than sufficiently powerful for its intended purposes. 
* JS is a loosely typed language. That means you do not have to declare the data types of variables explicitly. In fact, you cannot explicitly declare data types in JS. Moreover, in many cases JS performs conversions automatically when they are needed. For instance, if you try to add a number to an item that consists of text (a string), the number is converted to text.
* JS has a very powerful handling of associative arrays which is expanded to object properties, which can also be used in for-loops. Any functions can be assigned to and manipulated as a property. They even can be created by the new-operator.