JavaScript

Initially web pages were used by the academic and scientific community to share information, they were electric documents. As the web grew in popularity, and spread to the masses, a need for dynamic interaction and visually appealing sites became an issue.

Around 1995, Netscape developed the JavaScript programming language "LiveScript" and became an ECMA standard in 1997. ECMA-262 is the official name. ECMAScript 6 (released in June 2015) is the latest official version of JavaScript. JavaScript is a programming language designed for performing dynamic tasks. It is a scripting language which means it is parsed at runtime while programming languages are pre-compiled. It is the most popular programming language used to make web pages interactive. JavaScript has variables but not structured data types. It can be interpreted by the browsers. It is considered as a client-side scripting language and used to embed executable instruction in a web page. JavaScript contains a standard library of objects, such as Array, Date, and Math, and a core set of language elements such as operators, control structures, and statements. Core JavaScript can be extended for a variety of purposes by supplementing it with additional objects; for example:

• Client-side JavaScript extends the core language by supplying objects to control a browser and its Document Object Model (DOM). For example, client-side extensions allow an application to place elements on an HTML form and respond to user events such as mouse clicks, form input, and page navigation.

• Server-side JavaScript extends the core language by supplying objects relevant to running JavaScript on a server. For example, server-side extensions allow an application to communicate with a database, provide continuity of information from one invocation to another of the application, or perform file manipulations on a server.

 

What can JavaScript do?

• Retrieve date and time from user's computer.
• Determine user's Operating System, browser version, or screen resolution.
• Writing to the screen or the status bar of the window.
• Alert the users based on conditions(eg. entering incorrect information on a form).
• Perform mathematical calculations on the basis of data entered.
• Control features of the browsers like opening new browser window/tabs.

 

Is JavaScript similar to Java?

In some cases Java and JavaScript look similar but technically they are two different languages.

• The key difference is java is a programming language whereas JavaScript is a scripting language.
• Java creates applications that run in a virtual machine or browser while JavaScript code is run on a browser only.
• Java code needs to be compiled while JavaScript codes are all in text.
• JavaScript does not create applets or stand-alone applications. In its most common form, JavaScript resides inside HTML documents but Java applets run independent of the HTML document.
• JavaScript contains a much smaller and simpler set of commands than does Java.

 

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