The main differences betweenJScript and JScript .NET can be summarized as:
Firstly, JScript is ascripting language, and as such,programs (or more suggestively, scripts) can be executed with no need tocompile the code before. This is not the case with the JScript .NETcommand-line interface compiler, since this next-generation version relies on the .NETCommon Language Runtime (CLR) for execution, which requires that the code be compiled toCommon Intermediate Language (CIL), formerly named Microsoft Intermediate Language (MSIL), code before it can be run. Nevertheless, JScript .NET still fully supportsinterpretingsource code atruntime (e.g., via theFunction constructor or theeval function) and indeed the interpreter can be exposed by custom applications hosting the JScript .NET engine via the VSA[jargon] interfaces.
Secondly, JScript has a strong foundation in Microsoft'sActiveX andComponent Object Model (COM) technologies, and relies mainly on ActiveX components to provide much of its function (including database access viaActiveX Data Objects (ADO), file handling, etc.), whereas JScript .NET uses the.NET framework to provide equivalent function. For backward-compatibility (or for where no .NET equivalent library exists), JScript .NET still provides full access to ActiveX objects via .NET andCOM Interop using both the ActiveXObject constructor and the standard methods of the .NETType class.
Although the .NET framework and languages such asC# andVisual Basic (.NET) have been adopted widely, JScript .NET has received little attention, from the media and developers. It is not supported in Microsoft's premier development tool,Visual Studio .NET. However,ASP.NET supports JScript .NET.
JScript .NET does not require anentry point (main()function) that anoperating system must call directly when executing a JScript .NET application, as such, JScript .NET programcontrol flow can be based on global code.
JScript .NET, because of its very loosedata type checking system, can be easier to learn, since the common convention ofdeclaring types explicitly is unneeded.
JScript .NET does not require explicit references to the .NET framework Base Class Library, as certain functions found in earlier versions of JScript are present in JScript .NET (e.g., functions for finding thetangent of an angle for aright triangle).
JScript .NET is closely linked toC syntax, and is thus easy to learn forC#,Java, orC++ developers.
While JScript .NET can be used to create Windows Forms applications, it can have some trouble, as delegates can only be consumed in JScript .NET and not created. Thus, custom events are hard to emulate in JScript .NET.
JScript .NET does not need explicittype declaration on variables. (InC++, the use of templates and generics can be compared to this, loosely emulated with template specialization, etc.)
JScript .NET does not need explicittype casts on variable use in the program. Code used to retrieve a string of characters, but only used for integer numbers can be cast implicitly; the vice versa can be done without error atcompile time, but there is a chance of loss of precision or data.
e.g.:
importSystem;Console.WriteLine("Hello, what's your name?");Console.WriteLine("Type your name: ");varname:String=Console.ReadLine();Console.WriteLine($"Hello, {name}");
JScript .NET syntax and lexical conventions are similar toJava in that both are derived fromC. JScript was originally Microsoft's implementation ofECMAScript, which is more commonly known asJavaScript, though it is unrelated to Java. Thus, users of Java and other C-derived languages will find JScript easier to learn.
JScript .NET allows developers to useuntyped variables, and can sometimes infer their type from their usage to optimize the compiled code. On the other hand, Java requires all variables to be typed, though Java also supports type inference.
JScript .NET can add properties and methods to objects inrun-time, while Java objects always conform to their declared interface.
JScript .NET allows declaring variables and functions with type information (e.g.,var x: String;), while type information for JScript's variables and functions cannot be declared (e.g.,var x;).
JScript .NET scripts are not interpreted, but executed independently. When executed, a JScript .NET application will invoke theCLR. The CLR will execute theCIL instructions without using an interpreter.
JScript .NET can be run without the presence of a browser or anotherscripting engine as the compiler can generate standaloneexecutables and assemblies. However these still require.NET framework to be installed to run.
JScript .NET provides access to the .NET frameworkBase Class Library (BCL), providing much more function.
JScript .NET is available as a scripting language for onlyASP.NET, the technology used to generate web pages. Thus, JScript .NET has a role similar toPHP and otherserver-side scripting languages. Internet Explorer, however, still uses only the older JScript engine, so JScript.NET cannot be used to script web pages (orHTML Applications (HTAs), or HTCs). In this regard, JScript is much more versatile than JScript .NET.
Lists:JavaScript libraries •Ajax frameworks •Server-side JavaScript