Javascript Introduction

Javascript Introduction

Javascript Introduction :

Javascript Introduction – Javascript is a lightweight clientside(Browser) scripting language.

Using HTML & CSS we can design web pages, But can’t provide functionality.Using javascript We can provide behavior to web pages.

First of all JavaScript name is LiveScript, Finally Netscape changed its name to JavaScript.

javascript is a scripting language, so it has only one step that is “execution”.In execution time – we have another step that is “compilation”. This compilation is called as runtime compilation.

The browser can’t understand javascript directly, therefore need to pass javascript through HTML then only browser understand javascript.

JavaScript was initially created for client-side(Browser) web applications, but is now used in many other environments (Desktop/Server/Mobile).

JavaScript is standardized at Ecma International(ECMA – European Computer Manufacturers Association).This standardized version of JavaScriptis called ECMAScript.

Browser can understand upto ECMAScript5, Above versions need to convert ECMAScript5 for browser understanding purpose.

 

Javascript Introduction
Javascript-Introduction

How to write javscript code :

We have two way to apply javascript.

  1. Internal
  2. External

1.Internal Javascript:

<script>

//javascript code here…

</script>

2.External Javascript:

In any html file you can call a javascript file externally:

<script src=”filepath”/></script>

Javascript Features :

  1. Platform independent (or) Browser compatible :
    majority of web browsers have a dedicated JavaScript engine to execute javascript.
  2. Many frameworks developed on it
  3. User interaction through events
  4. Decrease burden on the server
  5. Generates dynamic content
  6. Supports local storage & session storage
  7. Events based scripting langauage
  8. object based (class free) technology

Javascript frameworks list

List of the technologies developed on javascript

  1. AngularJS
  2. Angular
  3. React.js
  4. Backbone.js
  5. Ember.js
  6. Express.js
  7. KnockoutJS
  8. Meteor
  9. Node.js
  10. OpenUI5
  11. Polymer
  12. Sails.js
  13. Vue.js

Server-side JavaScript

Netscape introduced server-side scripting with Netscape Enterprise Server. As a result

  1. Microsoft’s implementation of server-side Javascript (JScript) in ASP and .NET pages.
  2. Node.Js is also implemented using server-side javascript.

disadvantages of javascript

  1. JavaScript not support multi-threading or multiprocessing
    seems like java or dotnet.
  2. File reading & writing is not allowed by client-side javascript.
  3. Networking applications not suppose to use javascript.

In our next article, I will discuss variables

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