Introduction To JavaScript - History & Application Of JavaScript

Introduction To JavaScript - History Of JavaScript  Programming Language
Let’s see what’s so special about JavaScript, what we can achieve with it, and what other technologies play well with it.

What is a Script ?

Script or scripting language is a computer language with a series of commands within a file capable of being executed without being compiled. Scripting languages are usually interpreted at runtime rather than compiled.

Scripts (like PHP, Perl) which are executed on a web server are called server-side scripts and scripts (like JavaScript) which are executed on user's computer, interpreted by the browser is called client-side scripts.

What’s the difference between Scripting and Programming Languages?

Basically, all scripting languages are programming languages. The theoretical difference between the two is that scripting languages do not require the compilation step and are rather interpreted. For example, normally, a C program needs to be compiled before running whereas normally, a scripting language like JavaScript or PHP need not be compiled.

Applications of Scripting Languages :

1. To automate certain tasks in a program

2. Extracting information from a data set

3. Less code intensive as compared to traditional programming languages

Applications of Programming Languages :

1. They typically run inside a parent program like scripts

2. More compatible while integrating code with mathematical models

3. Languages like JAVA can be compiled and then used on any platform

What is JavaScript  Programming Language?

JavaScript is a popular programming language that has a wide range of applications.

JavaScript is a cross-platform, object-oriented scripting language developed by Netscape. JavaScript was initially created to “make web pages alive”.

The programs in this language are called scripts. They can be written right in a web page’s HTML and run automatically as the page loads.

History of JavaScript :

JavaScript was created by Netscape programmer Brendan Eich.

It was first released under the name of LiveScript as part of Netscape Navigator 2.0 in September 1995. It was renamed JavaScript on December 4, 1995. As JavaScript works on the client side, It is mostly used for client-side web development. But, in modern days JavaScript(JS) is used for both client side & server side web developments.

JavaScript is designed for use on web pages and closely integrated with HTML. JavaScript can create applications which run in the browsers such as IE, Opera, FireFox, Google Chrome and other. Netscape submitted JavaScript to ECMA International for standardization resulting in the standardized version named ECMAScript.

JavaScript Engines: 

Today, JavaScript can execute not only in the browser, but also on the server, or actually on any device that has a special program called the JavaScript engine.

The browser has an embedded engine sometimes called a “JavaScript virtual machine”.

Different engines have different “codenames”. For example:
  • V8 – in Chrome and Opera.
  • SpiderMonkey – in Firefox.

There are other codenames like “Chakra” for IE, “ChakraCore” for Microsoft Edge, “Nitro” and “SquirrelFish” for Safari, etc.

The terms above are good to remember because they are used in developer articles on the internet. We’ll use them too. For instance, if “a feature X is supported by V8”, then it probably works in Chrome and Opera.

Uses / Application of JavaScript:

  • Client-side validation
  • Dynamic drop-down menus
  • Displaying date and time
  • Validate user input in an HTML form before sending the data to a server.
  • Build forms that respond to user input without accessing a server.
  • Change the appearance of HTML documents and dynamically write HTML into separate Windows.
  • Open and close new windows or frames.
  • Manipulate HTML "layers" including hiding, moving, and allowing the user to drag them around a browser window.
  • Build small but complete client side programs .
  • Displaying popup windows and dialog boxes (like alert dialog box, confirm dialog box and prompt dialog box)
  • Displaying clocks etc.

Features of JavaScript:

JavaScript is a client side technology, it is mainly used for gives client side validation, but it have lot of features which are given below;

  • JavaScript is a object-based scripting language.
  • Giving the user more control over the browser.
  • It Handling dates and time.
  • It Detecting the user's browser and OS,
  • It is light weighted.
  • JavaScript is a scripting language and it is not java.
  • JavaScript is interpreter based scripting language.
  • JavaScript is case sensitive.
  • JavaScript is object based language as it provides predefined objects.
  • Every statement in javascript must be terminated with semicolon (;).
  • Most of the javascript control statements syntax is same as syntax of control statements in C language.
  • An important part of JavaScript is the ability to create new functions within scripts. Declare a function in JavaScript using function keyword.

Limitations of JavaScript:

JavaScript have some limitation which are given below;

  • Client-side JavaScript does not allow the reading or writing of files.
  • It cannot be used for networking applications because there is no such support available.
  • It doesn't have any multithreading or multiprocessor capabilities.

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