Key difference: JavaScript is an interpreted computer programming language. It is a prototype-based scripting language that is dynamic, weakly typed, and has first-class functions. VBScript, on the other hand, is an Active Scripting language. It is the Visual Basic Scripting Edition that has been developed by Microsoft. VBScript was designed to be a lightweight language with a fast interpreter.

Even though their names suggest that Java and JavaScript must be related somehow, it is just not true. JavaScript is an interpreted computer programming language. The main difference between Java and JavaScript is that while Java is a programming language, JavaScript is scripting language. It is a prototype-based scripting language that is dynamic, weakly typed, and has first-class functions. However, like Java, JavaScript is heavily influenced by the C programming language. JavaScript also borrows many names and naming conventions from Java, but it does have very different semantics than Java.

JavaScript takes its key design principles from the Self and Scheme programming languages. It is a multi-paradigm language that supports object-oriented, imperative, and functional programming styles.

JavaScript was formalized in the ECMAScript language standard and was originally implemented as part of web browsers. It allowed client-side scripts to interact with the user, control the browser, communicate asynchronously, and alter the document content that was displayed. However, JavaScript is also used in applications outside of web pages, such as in PDF documents, site-specific browsers, and desktop widgets. Furthermore, newer and faster JavaScript VMs and frameworks have also increased the popularity of JavaScript for server-side web applications.

There are various similarities between Java and JavaScript, such as both have a C-like syntax. They are both object-oriented and typically sandboxed, especially when used inside a browser. Also, JavaScript was designed with Java's syntax and standard library in mind. All Java keywords were reserved in original JavaScript. JavaScript's standard library follows Java's naming conventions, and JavaScript's Math and Date objects are based on classes from Java 1.0. However, they are much more different than they are similar.

VBScript, on the other hand, is an Active Scripting language. It is the Visual Basic Scripting Edition that has been developed by Microsoft. It is quite similar to Visual Basic, as it has been modeled on it. VBScript was designed to be a lightweight language with a fast interpreter.

However, majority of its uses were limited to Microsoft environments. Even now, VBScript is mainly supported by Internet Explorer. It has been installed by default in every desktop release of Microsoft Windows since Windows 98.  In addition to Internet Explorer, VBScript can also be executed on Windows Script Host (WSH) and Internet Information Services (IIS). Furthermore, VBScript can be embeddable in other programs through Microsoft Script Control.

VBScript is a general-purpose scripting language. It uses the Component Object Model to access elements of the environment within which it is running, such as the FileSystemObject (FSO) that is used to create, read, update and delete files. VBScript is commonly used among system administrators in the Microsoft environment. It is the scripting language for the test automation tool, Quick Test Professional. Even some embedded applications, such as industrial operator interfaces and human machine interfaces, have adopted VBScript as the internal scripting language.

The greatest advantage of VBScript is that it is easy to learn. Also, implementers need not pay royalties to Microsoft as long as the VBScript trade mark is acknowledged. 

Some differences between JavaScript and VBScript:

• JavaScript is often used to set and read cookies, display ads on various websites, shopping carts, and login systems. While, VBScript is used in embedded applications, and human machine interfaces.
• The syntax for JavaScript is similar to the syntax for the C++ programming language. Since VBScript is a subset of Visual Basic for Applications, VBScript follows the Visual Basic for Applications syntax.
• In Internet Explorer, both JavaScript and VBScript can read and modify HTML form elements, interact with the browser, and automate any ActiveX component.
• VBScript does not have an integrated debugging environment (IDE).
• JavaScript uses curly braces to denote functions, whereas VBScript uses Function…End Function and Sub…End Sub.
• JavaScript supports only functions, whereas VBScript supports functions and subroutines.
• Neither JavaScript nor VBScript is truly object-oriented.
• Neither JavaScript nor VBScript supports the concept of inheritance.
• JavaScript makes stronger use of objects than does VBScript.
• JavaScript allows for the definition of classes for the subsequent creation of objects.
• VBScript does not support object creation or user-defined classes.
• VBScript supports reusable functions and subroutines.
• JavaScript is case sensitive, while VBScript is not.
• VBScript is both a client and server-side scripting language, while JavaScript is only a client-side scripting language.
• JavaScript is the default scripting language for most browsers, while VBScript is not. It must be specified as the scripting language.
• The file extension for VBScript is .vbs or .vba; the file extension for JavaScript is .js.

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